From 22b204376180b2d1cc52918cefce859050b21626 Mon Sep 17 00:00:00 2001
From: "jonah.m.delaney@gmail.com" <halfday@Macbooks-MacBook-Pro-8.local>
Date: Thu, 20 Sep 2018 16:02:04 -0500
Subject: [PATCH 1/7] finished factorial

---
 src/recursion.js | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/recursion.js b/src/recursion.js
index 12ca0a3d7..194e77fb9 100644
--- a/src/recursion.js
+++ b/src/recursion.js
@@ -4,32 +4,46 @@
 // denoted by n!, is the product of all positive integers less than or equal to n.
 // Example:  5! = 5 x 4 x 3 x 2 x 1 = 120
 // factorial(5);  // 120
-var factorial = function(n) {
+var factorial = function(n, sum=1, i=n) {
+    if (n < 0) {return null;}
+    if (i === 0) {return sum;}
+    sum *= i;
+    i--;
+    return factorial(n - 1, sum);
 };
 
 // 2. Compute the sum of an array of integers.
 // Example:  sum([1, 2, 3, 4, 5, 6]);  // 21
-var sum = function(array) {
+var sum = function(array, total=0, i=array.length-1) {
+    if (!array.length) {return 0;}
+    total += array[i];
+    i++;
+    sum(array.slice(1), total, i);
+    return total;
 };
 
 // 3. Sum all numbers in an array containing nested arrays.
 // Example: arraySum([1,[2,3],[[4]],5]); // 15
 var arraySum = function(array) {
+
 };
 
 // 4. Check if a number is even.
 var isEven = function(n) {
+
 };
 
 // 5. Sum all integers below a given integer.
 // sumBelow(10); // 45
 // sumBelow(7); // 21
 var sumBelow = function(n) {
+
 };
 
 // 6. Get the integers in range (x, y).
 // Example:  range(2, 9);  // [3, 4, 5, 6, 7, 8]
 var range = function(x, y) {
+
 };
 
 // 7. Compute the exponent of a number.

From 4ceada6bed1bd449380a66e4a5b0a38730a35ef8 Mon Sep 17 00:00:00 2001
From: "jonah.m.delaney@gmail.com" <halfday@Macbooks-MacBook-Pro-8.local>
Date: Fri, 21 Sep 2018 15:59:42 -0500
Subject: [PATCH 2/7] finished sum, sumBelow, isEven, and started range

---
 src/recursion.js | 122 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 77 insertions(+), 45 deletions(-)

diff --git a/src/recursion.js b/src/recursion.js
index 194e77fb9..47a0ee80e 100644
--- a/src/recursion.js
+++ b/src/recursion.js
@@ -4,9 +4,9 @@
 // denoted by n!, is the product of all positive integers less than or equal to n.
 // Example:  5! = 5 x 4 x 3 x 2 x 1 = 120
 // factorial(5);  // 120
-var factorial = function(n, sum=1, i=n) {
-    if (n < 0) {return null;}
-    if (i === 0) {return sum;}
+var factorial = function (n, sum = 1, i = n) {
+    if (n < 0) { return null; }
+    if (i === 0) { return sum; }
     sum *= i;
     i--;
     return factorial(n - 1, sum);
@@ -14,36 +14,68 @@ var factorial = function(n, sum=1, i=n) {
 
 // 2. Compute the sum of an array of integers.
 // Example:  sum([1, 2, 3, 4, 5, 6]);  // 21
-var sum = function(array, total=0, i=array.length-1) {
-    if (!array.length) {return 0;}
+var sum = function (array, total = 0, i = 0) {
+    if (i >= array.length) {
+        return total;
+    }
     total += array[i];
     i++;
-    sum(array.slice(1), total, i);
-    return total;
+    return sum(array, total, i);
 };
 
 // 3. Sum all numbers in an array containing nested arrays.
 // Example: arraySum([1,[2,3],[[4]],5]); // 15
-var arraySum = function(array) {
+var arraySum = function (array) {
 
 };
 
 // 4. Check if a number is even.
-var isEven = function(n) {
-
+var isEven = function (n, i = n) {
+    if (i - 2 === 0) {
+        return boolean = true;
+    } else if (i - 2 > 0) {
+        i -= 2;
+        boolean = false;
+        return isEven(n, i, boolean);
+    } else if (i + 2 === 0) {
+        return boolean = true;
+    } else if (i + 2 < 0) {
+        i += 2;
+        boolean = false;
+        return isEven(n, i, boolean);
+    }
+    return boolean;
 };
 
 // 5. Sum all integers below a given integer.
 // sumBelow(10); // 45
 // sumBelow(7); // 21
-var sumBelow = function(n) {
-
+var sumBelow = function (n, sum = 0, i = n) {
+    if (n === 0) { return sum; }
+    if (n > 0) {
+        i = n - 1;
+        sum += i;
+        i--;
+        return sumBelow(n - 1, sum, i);
+    } else if (n < 0) {
+        i = n + 1;
+        sum += i;
+        i++;
+        return sumBelow(n + 1, sum, i);
+    }
+    return sum;
 };
 
 // 6. Get the integers in range (x, y).
 // Example:  range(2, 9);  // [3, 4, 5, 6, 7, 8]
-var range = function(x, y) {
-
+var range = function (x, y, arr = []) {
+    if (x === y) { return arr;}
+    if (x !== y) {
+        x++;
+        arr.push(x);
+        return range(x, y, arr);
+    }
+    return arr;
 };
 
 // 7. Compute the exponent of a number.
@@ -51,22 +83,22 @@ var range = function(x, y) {
 // 8^2 = 8 x 8 = 64.  Here, 8 is the base and 2 is the exponent.
 // Example:  exponent(4,3);  // 64
 // https://www.khanacademy.org/computing/computer-science/algorithms/recursive-algorithms/a/computing-powers-of-a-number
-var exponent = function(base, exp) {
+var exponent = function (base, exp) {
 };
 
 // 8. Determine if a number is a power of two.
 // powerOfTwo(1); // true
 // powerOfTwo(16); // true
 // powerOfTwo(10); // false
-var powerOfTwo = function(n) {
+var powerOfTwo = function (n) {
 };
 
 // 9. Write a function that accepts a string a reverses it.
-var reverse = function(string) {
+var reverse = function (string) {
 };
 
 // 10. Write a function that determines if a string is a palindrome.
-var palindrome = function(string) {
+var palindrome = function (string) {
 };
 
 // 11. Write a function that returns the remainder of x divided by y without using the
@@ -74,17 +106,17 @@ var palindrome = function(string) {
 // modulo(5,2) // 1
 // modulo(17,5) // 2
 // modulo(22,6) // 4
-var modulo = function(x, y) {
+var modulo = function (x, y) {
 };
 
 // 12. Write a function that multiplies two numbers without using the * operator  or
 // JavaScript's Math object.
-var multiply = function(x, y) {
+var multiply = function (x, y) {
 };
 
 // 13. Write a function that divides two numbers without using the / operator  or
 // JavaScript's Math object.
-var divide = function(x, y) {
+var divide = function (x, y) {
 };
 
 // 14. Find the greatest common divisor (gcd) of two positive numbers.  The GCD of two
@@ -92,7 +124,7 @@ var divide = function(x, y) {
 // Example:  gcd(4,36);  // 4
 // http://www.cse.wustl.edu/~kjg/cse131/Notes/Recursion/recursion.html
 // https://www.khanacademy.org/computing/computer-science/cryptography/modarithmetic/a/the-euclidean-algorithm
-var gcd = function(x, y) {
+var gcd = function (x, y) {
 };
 
 // 15. Write a function that compares each character of two strings and returns true if
@@ -100,12 +132,12 @@ var gcd = function(x, y) {
 // compareStr('house', 'houses') // false
 // compareStr('', '') // true
 // compareStr('tomato', 'tomato') // true
-var compareStr = function(str1, str2) {
+var compareStr = function (str1, str2) {
 };
 
 // 16. Write a function that accepts a string and creates an array where each letter
 // occupies an index of the array.
-var createArray = function(str){
+var createArray = function (str) {
 };
 
 // 17. Reverse the order of an array
@@ -115,37 +147,37 @@ var reverseArr = function (array) {
 // 18. Create a new array with a given value and length.
 // buildList(0,5) // [0,0,0,0,0]
 // buildList(7,3) // [7,7,7]
-var buildList = function(value, length) {
+var buildList = function (value, length) {
 };
 
 // 19. Count the occurence of a value inside a list.
 // countOccurrence([2,7,4,4,1,4], 4) // 3
 // countOccurrence([2,'banana',4,4,1,'banana'], 'banana') // 2
-var countOccurrence = function(array, value) {
+var countOccurrence = function (array, value) {
 };
 
 // 20. Write a recursive version of map.
 // rMap([1,2,3], timesTwo); // [2,4,6]
-var rMap = function(array, callback) {
+var rMap = function (array, callback) {
 };
 
 // 21. Write a function that counts the number of times a key occurs in an object.
 // var testobj = {'e': {'x':'y'}, 't':{'r': {'e':'r'}, 'p': {'y':'r'}},'y':'e'};
 // countKeysInObj(testobj, 'r') // 1
 // countKeysInObj(testobj, 'e') // 2
-var countKeysInObj = function(obj, key) {
+var countKeysInObj = function (obj, key) {
 };
 
 // 22. Write a function that counts the number of times a value occurs in an object.
 // var testobj = {'e': {'x':'y'}, 't':{'r': {'e':'r'}, 'p': {'y':'r'}},'y':'e'};
 // countValuesInObj(testobj, 'r') // 2
 // countValuesInObj(testobj, 'e') // 1
-var countValuesInObj = function(obj, value) {
+var countValuesInObj = function (obj, value) {
 };
 
 // 23. Find all keys in an object (and nested objects) by a provided name and rename
 // them to a provided new name while preserving the value stored at that key.
-var replaceKeysInObj = function(obj, key, newKey) {
+var replaceKeysInObj = function (obj, key, newKey) {
 };
 
 // 24. Get the first n Fibonacci numbers.  In the Fibonacci Sequence, each subsequent
@@ -153,7 +185,7 @@ var replaceKeysInObj = function(obj, key, newKey) {
 // Example:  0, 1, 1, 2, 3, 5, 8, 13, 21, 34.....
 // fibonacci(5);  // [0, 1, 1, 2, 3, 5]
 // Note:  The 0 is not counted.
-var fibonacci = function(n) {
+var fibonacci = function (n) {
 };
 
 // 25. Return the Fibonacci number located at index n of the Fibonacci sequence.
@@ -161,18 +193,18 @@ var fibonacci = function(n) {
 // nthFibo(5); // 5
 // nthFibo(7); // 13
 // nthFibo(3); // 2
-var nthFibo = function(n) {
+var nthFibo = function (n) {
 };
 
 // 26. Given an array of words, return a new array containing each word capitalized.
 // var words = ['i', 'am', 'learning', 'recursion'];
 // capitalizedWords(words); // ['I', 'AM', 'LEARNING', 'RECURSION']
-var capitalizeWords = function(input) {
+var capitalizeWords = function (input) {
 };
 
 // 27. Given an array of strings, capitalize the first letter of each index.
 // capitalizeFirst(['car', 'poop', 'banana']); // ['Car', 'Poop', 'Banana']
-var capitalizeFirst = function(array) {
+var capitalizeFirst = function (array) {
 };
 
 // 28. Return the sum of all even numbers in an object containing nested objects.
@@ -184,17 +216,17 @@ var capitalizeFirst = function(array) {
 //   e: {e: {e: 2}, ee: 'car'}
 // };
 // nestedEvenSum(obj1); // 10
-var nestedEvenSum = function(obj) {
+var nestedEvenSum = function (obj) {
 };
 
 // 29. Flatten an array containing nested arrays.
 // Example: flatten([1,[2],[3,[[4]]],5]); // [1,2,3,4,5]
-var flatten = function(arrays) {
+var flatten = function (arrays) {
 };
 
 // 30. Given a string, return an object containing tallies of each letter.
 // letterTally('potato'); // {'p':1, 'o':2, 't':2, 'a':1}
-var letterTally = function(str, obj) {
+var letterTally = function (str, obj) {
 };
 
 // 31. Eliminate consecutive duplicates in a list.  If the list contains repeated
@@ -202,51 +234,51 @@ var letterTally = function(str, obj) {
 // elements should not be changed.
 // Example: compress([1, 2, 2, 3, 4, 4, 5, 5, 5]) // [1, 2, 3, 4, 5]
 // Example: compress([1, 2, 2, 3, 4, 4, 2, 5, 5, 5, 4, 4]) // [1, 2, 3, 4, 2, 5, 4]
-var compress = function(list) {
+var compress = function (list) {
 };
 
 // 32. Augment every element in a list with a new value where each element is an array
 // itself.
 // Example: augmentElements([[],[3],[7]], 5); // [[5],[3,5],[7,5]]
-var augmentElements = function(array, aug) {
+var augmentElements = function (array, aug) {
 };
 
 // 33. Reduce a series of zeroes to a single 0.
 // minimizeZeroes([2,0,0,0,1,4]) // [2,0,1,4]
 // minimizeZeroes([2,0,0,0,1,0,0,4]) // [2,0,1,0,4]
-var minimizeZeroes = function(array) {
+var minimizeZeroes = function (array) {
 };
 
 // 34. Alternate the numbers in an array between positive and negative regardless of
 // their original sign.  The first number in the index always needs to be positive.
 // alternateSign([2,7,8,3,1,4]) // [2,-7,8,-3,1,-4]
 // alternateSign([-2,-7,8,3,-1,4]) // [2,-7,8,-3,1,-4]
-var alternateSign = function(array) {
+var alternateSign = function (array) {
 };
 
 // 35. Given a string, return a string with digits converted to their word equivalent.
 // Assume all numbers are single digits (less than 10).
 // numToText("I have 5 dogs and 6 ponies"); // "I have five dogs and six ponies"
-var numToText = function(str) {
+var numToText = function (str) {
 };
 
 // *** EXTRA CREDIT ***
 
 // 36. Return the number of times a tag occurs in the DOM.
-var tagCount = function(tag, node) {
+var tagCount = function (tag, node) {
 };
 
 // 37. Write a function for binary search.
 // Sample array:  [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
 // console.log(binarySearch(5)) will return '5'
 
-var binarySearch = function(array, target, min, max) {
+var binarySearch = function (array, target, min, max) {
 };
 
 // 38. Write a merge sort function.
 // Sample array:  [34,7,23,32,5,62]
 // Sample output: [5,7,23,32,34,62]
-var mergeSort = function(array) {
+var mergeSort = function (array) {
 };
 
 

From 4a75a3edc275e17f18af2d04ac3fbad3c7e5fd5b Mon Sep 17 00:00:00 2001
From: "jonah.m.delaney@gmail.com" <halfday@Macbooks-MacBook-Pro-8.local>
Date: Mon, 24 Sep 2018 15:55:25 -0500
Subject: [PATCH 3/7] finished exponent, power of two, and started palindrome

---
 src/recursion.js | 50 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 5 deletions(-)

diff --git a/src/recursion.js b/src/recursion.js
index 47a0ee80e..32fd83b73 100644
--- a/src/recursion.js
+++ b/src/recursion.js
@@ -69,8 +69,16 @@ var sumBelow = function (n, sum = 0, i = n) {
 // 6. Get the integers in range (x, y).
 // Example:  range(2, 9);  // [3, 4, 5, 6, 7, 8]
 var range = function (x, y, arr = []) {
-    if (x === y) { return arr;}
-    if (x !== y) {
+    if (x === y) { return arr; }
+    if (x > y) {
+        if (y !== x - 1) {
+            x--;
+            arr.push(x);
+            return range(x, y, arr);
+        }
+        return arr; 0.
+    }
+    if (x !== y - 1) {
         x++;
         arr.push(x);
         return range(x, y, arr);
@@ -83,22 +91,54 @@ var range = function (x, y, arr = []) {
 // 8^2 = 8 x 8 = 64.  Here, 8 is the base and 2 is the exponent.
 // Example:  exponent(4,3);  // 64
 // https://www.khanacademy.org/computing/computer-science/algorithms/recursive-algorithms/a/computing-powers-of-a-number
-var exponent = function (base, exp) {
+var exponent = function (base, exp, i = exp, total = 1) {
+    if (exp === 0) { return 1; }
+    if (exp === 1) { return base; }
+    if (i === 0) { return total; }
+    if (i > 0) {
+        total *= base;
+        i--;
+        return exponent(base, exp, i, total);
+    }
+    if (i < 0) {
+        total /= base;
+        i++;
+        return exponent(base, exp, i, total);
+    }
+    return total;
 };
 
 // 8. Determine if a number is a power of two.
 // powerOfTwo(1); // true
 // powerOfTwo(16); // true
 // powerOfTwo(10); // false
-var powerOfTwo = function (n) {
+var powerOfTwo = function (n, x = 1) {
+    if (x === n) { return true; }
+    if (x > n) { return false; }
+    if (x < n) {
+        x *= 2;
+        return powerOfTwo(n, x);
+    }
 };
 
 // 9. Write a function that accepts a string a reverses it.
 var reverse = function (string) {
+    if (string === "") {return "";}
+    else {
+        return reverse(string.substr(1)) + string.charAt(0);
+    }
 };
 
 // 10. Write a function that determines if a string is a palindrome.
-var palindrome = function (string) {
+var palindrome = function (string, i = 0) {
+    if (string = reverse(string)) {
+        return true;
+    }
+    if (i <= 3) {
+        i++;
+        return palindrome(string, i);
+    }
+    return false;
 };
 
 // 11. Write a function that returns the remainder of x divided by y without using the

From a4b39265e93795de44812404fb2dd2b79325e239 Mon Sep 17 00:00:00 2001
From: "jonah.m.delaney@gmail.com" <halfday@Macbooks-MacBook-Pro-8.local>
Date: Tue, 25 Sep 2018 15:57:17 -0500
Subject: [PATCH 4/7] finished a lot

---
 src/recursion.js | 108 ++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 89 insertions(+), 19 deletions(-)

diff --git a/src/recursion.js b/src/recursion.js
index 32fd83b73..279283ace 100644
--- a/src/recursion.js
+++ b/src/recursion.js
@@ -123,22 +123,27 @@ var powerOfTwo = function (n, x = 1) {
 
 // 9. Write a function that accepts a string a reverses it.
 var reverse = function (string) {
-    if (string === "") {return "";}
+    if (string === "") { return ""; }
     else {
         return reverse(string.substr(1)) + string.charAt(0);
     }
 };
 
 // 10. Write a function that determines if a string is a palindrome.
-var palindrome = function (string, i = 0) {
-    if (string = reverse(string)) {
-        return true;
-    }
-    if (i <= 3) {
+var palindrome = function (string, boolean = false, reverseString = function (string) {
+    if (string === "") { return ""; }
+    else { return reverseString(string.substr(1)) + string.charAt(0); }
+}, i = 0) {
+
+    if (string.charAt(0) === reverseString(string).charAt(0 + i)) {
         i++;
-        return palindrome(string, i);
+        return palindrome(string.slice(1));
+    } else if (string.charAt(0) !== reverseString(string).charAt(0)) {
+        return true;
     }
-    return false;
+    // [1, 2, 3, 4, 5, 6]
+    // i = 0;
+    // x = string.length - (i + 1);
 };
 
 // 11. Write a function that returns the remainder of x divided by y without using the
@@ -151,7 +156,20 @@ var modulo = function (x, y) {
 
 // 12. Write a function that multiplies two numbers without using the * operator  or
 // JavaScript's Math object.
-var multiply = function (x, y) {
+var multiply = function (x, y, i = y, total = 0) {
+    if (x === 0 || y === 0) { return 0; }
+    if (i === 0 && y > 0) { return total; }
+    if (i === 0 && y < 0) { return -total; }
+    if (y > 0) {
+        total += x;
+        i--;
+        return multiply(x, y, i, total);
+    }
+    if (y < 0) {
+        total += x;
+        i++;
+        return multiply(x, y, i, total);
+    }
 };
 
 // 13. Write a function that divides two numbers without using the / operator  or
@@ -172,33 +190,71 @@ var gcd = function (x, y) {
 // compareStr('house', 'houses') // false
 // compareStr('', '') // true
 // compareStr('tomato', 'tomato') // true
-var compareStr = function (str1, str2) {
+var compareStr = function (str1, str2, i = 0) {
+    if (i === str1.length && i === str2.length) { return true; }
+    if (str1.charAt(i) !== str2.charAt(i)) {
+        return false;
+    } else if (str1.charAt(i) === str2.charAt(i)) {
+        i++;
+        return compareStr(str1, str2, i);
+    }
+    return true;
 };
 
 // 16. Write a function that accepts a string and creates an array where each letter
 // occupies an index of the array.
-var createArray = function (str) {
+var createArray = function (string, i = 0, array = []) {
+    if (i === string.length) { return array; }
+    if (string.charAt(i)) {
+        array.push(string.charAt(i));
+        i++;
+        return createArray(string, i, array);
+    }
+    return array;
 };
 
 // 17. Reverse the order of an array
-var reverseArr = function (array) {
+var reverseArr = function (array, i = array.length - 1, newArr = []) {
+    if (i === -1) { return newArr; }
+    if (i >= 0) {
+        newArr.push(array[i]);
+        i--;
+        return reverseArr(array, i, newArr);
+    }
 };
 
 // 18. Create a new array with a given value and length.
 // buildList(0,5) // [0,0,0,0,0]
 // buildList(7,3) // [7,7,7]
-var buildList = function (value, length) {
+var buildList = function (value, length, i = 0, array = []) {
+    if (i === length) { return array; }
+    array.push(value);
+    i++;
+    return buildList(value, length, i, array);
 };
 
 // 19. Count the occurence of a value inside a list.
 // countOccurrence([2,7,4,4,1,4], 4) // 3
 // countOccurrence([2,'banana',4,4,1,'banana'], 'banana') // 2
-var countOccurrence = function (array, value) {
+var countOccurrence = function (array, value, i = 0, x = 0) {
+    if (i === array.length) { return x; }
+    if (array[i] === value) {
+        i++;
+        x++;
+        return countOccurrence(array, value, i, x);
+    } else {
+        i++;
+        return countOccurrence(array, value, i, x);
+    }
 };
 
 // 20. Write a recursive version of map.
 // rMap([1,2,3], timesTwo); // [2,4,6]
-var rMap = function (array, callback) {
+var rMap = function (array, callback, i = 0, newArr = []) {
+    if (i === array.length) { return newArr; }
+    newArr.push(callback(array[i]));
+    i++;
+    return rMap(array, callback, i, newArr);
 };
 
 // 21. Write a function that counts the number of times a key occurs in an object.
@@ -233,18 +289,32 @@ var fibonacci = function (n) {
 // nthFibo(5); // 5
 // nthFibo(7); // 13
 // nthFibo(3); // 2
-var nthFibo = function (n) {
+var nthFibo = function (n, i = 0, array = [0, 1]) {
+    if (i === n) { return array[i]; }
+    if (n < 0) { return null; }
+    array.push(array[i] + array[i + 1]);
+    i++;
+    return nthFibo(n, i, array)
 };
 
 // 26. Given an array of words, return a new array containing each word capitalized.
 // var words = ['i', 'am', 'learning', 'recursion'];
 // capitalizedWords(words); // ['I', 'AM', 'LEARNING', 'RECURSION']
-var capitalizeWords = function (input) {
-};
+var capitalizeWords = function (input, array = [], i = 0) {
+    if (input.length === array.length) { return array; }
+    array.push(input[i].toUpperCase());
+    i++;
+    return capitalizeWords(input, array, i);
+}
 
 // 27. Given an array of strings, capitalize the first letter of each index.
 // capitalizeFirst(['car', 'poop', 'banana']); // ['Car', 'Poop', 'Banana']
-var capitalizeFirst = function (array) {
+var capitalizeFirst = function (array, newArr = [], i = 0) {
+    if (array.length === newArr.length) {return array;}
+    newArr.push(array[i]);
+    newArr.charAt(0).toUpperCase();
+    i++;
+    return capitalizeFirst(array, newArr, i);
 };
 
 // 28. Return the sum of all even numbers in an object containing nested objects.

From 275556b64fe53a540e32c3dfe520446f38507674 Mon Sep 17 00:00:00 2001
From: "jonah.m.delaney@gmail.com" <halfday@Macbooks-MacBook-Pro-8.local>
Date: Wed, 26 Sep 2018 15:55:37 -0500
Subject: [PATCH 5/7] we done did a whole lot thanks to a duck...

---
 src/recursion.js | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/src/recursion.js b/src/recursion.js
index 279283ace..62c4d9a66 100644
--- a/src/recursion.js
+++ b/src/recursion.js
@@ -310,9 +310,8 @@ var capitalizeWords = function (input, array = [], i = 0) {
 // 27. Given an array of strings, capitalize the first letter of each index.
 // capitalizeFirst(['car', 'poop', 'banana']); // ['Car', 'Poop', 'Banana']
 var capitalizeFirst = function (array, newArr = [], i = 0) {
-    if (array.length === newArr.length) {return array;}
-    newArr.push(array[i]);
-    newArr.charAt(0).toUpperCase();
+    if (array.length === newArr.length) { return newArr; }
+    newArr.push(array[i].charAt(0).toUpperCase() + array[i].slice(1));
     i++;
     return capitalizeFirst(array, newArr, i);
 };
@@ -336,7 +335,22 @@ var flatten = function (arrays) {
 
 // 30. Given a string, return an object containing tallies of each letter.
 // letterTally('potato'); // {'p':1, 'o':2, 't':2, 'a':1}
-var letterTally = function (str, obj) {
+var letterTally = function (string, object = {}, array = [], i = 0, key = array[i]) {
+    if (i === string.length) { return object; }
+    if (string.length > array.length) {
+        array.push(string.charAt(i));
+        i++;
+        return letterTally(string, object, array, i, array[i]);
+    }
+
+    if (array.length === string.length) {
+        i = 0;
+        object[key] = countOccurrence(array, array[i], i);
+        return letterTally(string, object, array, i, array[i]);
+    }
+
+return object;
+
 };
 
 // 31. Eliminate consecutive duplicates in a list.  If the list contains repeated
@@ -363,7 +377,7 @@ var minimizeZeroes = function (array) {
 // their original sign.  The first number in the index always needs to be positive.
 // alternateSign([2,7,8,3,1,4]) // [2,-7,8,-3,1,-4]
 // alternateSign([-2,-7,8,3,-1,4]) // [2,-7,8,-3,1,-4]
-var alternateSign = function (array) {
+var alternateSign = function (array, i = 1, newArr = [array[0]]) {
 };
 
 // 35. Given a string, return a string with digits converted to their word equivalent.

From 54de4835c3d3c19c6b836d918e46b19d20f199a3 Mon Sep 17 00:00:00 2001
From: JonahDelaney <jonah.m.delaney@gmail.com>
Date: Wed, 26 Sep 2018 20:32:48 -0500
Subject: [PATCH 6/7] Add files via upload

---
 recursion.js | 464 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 464 insertions(+)
 create mode 100644 recursion.js

diff --git a/recursion.js b/recursion.js
new file mode 100644
index 000000000..e876a0557
--- /dev/null
+++ b/recursion.js
@@ -0,0 +1,464 @@
+// Solve all of the following prompts using recursion.
+
+// 1. Calculate the factorial of a number.  The factorial of a non-negative integer n,
+// denoted by n!, is the product of all positive integers less than or equal to n.
+// Example:  5! = 5 x 4 x 3 x 2 x 1 = 120
+// factorial(5);  // 120
+var factorial = function (n, sum = 1, i = n) {
+    if (n < 0) { return null; }
+    if (i === 0) { return sum; }
+    sum *= i;
+    i--;
+    return factorial(n - 1, sum);
+};
+
+// 2. Compute the sum of an array of integers.
+// Example:  sum([1, 2, 3, 4, 5, 6]);  // 21
+var sum = function (array, total = 0, i = 0) {
+    if (i >= array.length) {
+        return total;
+    }
+    total += array[i];
+    i++;
+    return sum(array, total, i);
+};
+
+// 3. Sum all numbers in an array containing nested arrays.
+// Example: arraySum([1,[2,3],[[4]],5]); // 15
+var arraySum = function (array) {
+
+};
+
+// 4. Check if a number is even.
+var isEven = function (n, i = n) {
+    if (i - 2 === 0) {
+        return boolean = true;
+    } else if (i - 2 > 0) {
+        i -= 2;
+        boolean = false;
+        return isEven(n, i, boolean);
+    } else if (i + 2 === 0) {
+        return boolean = true;
+    } else if (i + 2 < 0) {
+        i += 2;
+        boolean = false;
+        return isEven(n, i, boolean);
+    }
+    return boolean;
+};
+
+// 5. Sum all integers below a given integer.
+// sumBelow(10); // 45
+// sumBelow(7); // 21
+var sumBelow = function (n, sum = 0, i = n) {
+    if (n === 0) { return sum; }
+    if (n > 0) {
+        i = n - 1;
+        sum += i;
+        i--;
+        return sumBelow(n - 1, sum, i);
+    } else if (n < 0) {
+        i = n + 1;
+        sum += i;
+        i++;
+        return sumBelow(n + 1, sum, i);
+    }
+    return sum;
+};
+
+// 6. Get the integers in range (x, y).
+// Example:  range(2, 9);  // [3, 4, 5, 6, 7, 8]
+var range = function (x, y, arr = []) {
+    if (x === y) { return arr; }
+    if (x > y) {
+        if (y !== x - 1) {
+            x--;
+            arr.push(x);
+            return range(x, y, arr);
+        }
+        return arr; 0.
+    }
+    if (x !== y - 1) {
+        x++;
+        arr.push(x);
+        return range(x, y, arr);
+    }
+    return arr;
+};
+
+// 7. Compute the exponent of a number.
+// The exponent of a number says how many times the base number is used as a factor.
+// 8^2 = 8 x 8 = 64.  Here, 8 is the base and 2 is the exponent.
+// Example:  exponent(4,3);  // 64
+// https://www.khanacademy.org/computing/computer-science/algorithms/recursive-algorithms/a/computing-powers-of-a-number
+var exponent = function (base, exp, i = exp, total = 1) {
+    if (exp === 0) { return 1; }
+    if (exp === 1) { return base; }
+    if (i === 0) { return total; }
+    if (i > 0) {
+        total *= base;
+        i--;
+        return exponent(base, exp, i, total);
+    }
+    if (i < 0) {
+        total /= base;
+        i++;
+        return exponent(base, exp, i, total);
+    }
+    return total;
+};
+
+// 8. Determine if a number is a power of two.
+// powerOfTwo(1); // true
+// powerOfTwo(16); // true
+// powerOfTwo(10); // false
+var powerOfTwo = function (n, x = 1) {
+    if (x === n) { return true; }
+    if (x > n) { return false; }
+    if (x < n) {
+        x *= 2;
+        return powerOfTwo(n, x);
+    }
+};
+
+// 9. Write a function that accepts a string a reverses it.
+var reverse = function (string) {
+    if (string === "") { return ""; }
+    else {
+        return reverse(string.substr(1)) + string.charAt(0);
+    }
+};
+
+// 10. Write a function that determines if a string is a palindrome.
+var palindrome = function (string, i = string.length - 1, back = "") {
+    string = string.replace(" ", "");
+    back = back.replace(" ", "");
+    if (i < 0) {
+        if (back.toLowerCase() == string.toLowerCase()) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+    back = back.concat(string.charAt(i));
+    i--;
+    return palindrome(string, i, back);
+};
+
+// 11. Write a function that returns the remainder of x divided by y without using the
+// modulo (%) operator.
+// modulo(5,2) // 1
+// modulo(17,5) // 2
+// modulo(22,6) // 4
+var modulo = function (x, y) {
+};
+
+// 12. Write a function that multiplies two numbers without using the * operator  or
+// JavaScript's Math object.
+var multiply = function (x, y, i = y, total = 0) {
+    if (x === 0 || y === 0) { return 0; }
+    if (i === 0 && y > 0) { return total; }
+    if (i === 0 && y < 0) { return -total; }
+    if (y > 0) {
+        total += x;
+        i--;
+        return multiply(x, y, i, total);
+    }
+    if (y < 0) {
+        total += x;
+        i++;
+        return multiply(x, y, i, total);
+    }
+};
+
+// 13. Write a function that divides two numbers without using the / operator  or
+// JavaScript's Math object.
+var divide = function (x, y) {
+};
+
+// 14. Find the greatest common divisor (gcd) of two positive numbers.  The GCD of two
+// integers is the greatest integer that divides both x and y with no remainder.
+// Example:  gcd(4,36);  // 4
+// http://www.cse.wustl.edu/~kjg/cse131/Notes/Recursion/recursion.html
+// https://www.khanacademy.org/computing/computer-science/cryptography/modarithmetic/a/the-euclidean-algorithm
+var gcd = function (x, y) {
+};
+
+// 15. Write a function that compares each character of two strings and returns true if
+// both are identical.
+// compareStr('house', 'houses') // false
+// compareStr('', '') // true
+// compareStr('tomato', 'tomato') // true
+var compareStr = function (str1, str2, i = 0) {
+    if (i === str1.length && i === str2.length) { return true; }
+    if (str1.charAt(i) !== str2.charAt(i)) {
+        return false;
+    } else if (str1.charAt(i) === str2.charAt(i)) {
+        i++;
+        return compareStr(str1, str2, i);
+    }
+    return true;
+};
+
+// 16. Write a function that accepts a string and creates an array where each letter
+// occupies an index of the array.
+var createArray = function (string, i = 0, array = []) {
+    if (i === string.length) { return array; }
+    if (string.charAt(i)) {
+        array.push(string.charAt(i));
+        i++;
+        return createArray(string, i, array);
+    }
+    return array;
+};
+
+// 17. Reverse the order of an array
+var reverseArr = function (array, i = array.length - 1, newArr = []) {
+    if (i === -1) { return newArr; }
+    if (i >= 0) {
+        newArr.push(array[i]);
+        i--;
+        return reverseArr(array, i, newArr);
+    }
+};
+
+// 18. Create a new array with a given value and length.
+// buildList(0,5) // [0,0,0,0,0]
+// buildList(7,3) // [7,7,7]
+var buildList = function (value, length, i = 0, array = []) {
+    if (i === length) { return array; }
+    array.push(value);
+    i++;
+    return buildList(value, length, i, array);
+};
+
+// 19. Count the occurence of a value inside a list.
+// countOccurrence([2,7,4,4,1,4], 4) // 3
+// countOccurrence([2,'banana',4,4,1,'banana'], 'banana') // 2
+var countOccurrence = function (array, value, i = 0, x = 0) {
+    if (i === array.length) { return x; }
+    if (array[i] === value) {
+        i++;
+        x++;
+        return countOccurrence(array, value, i, x);
+    } else {
+        i++;
+        return countOccurrence(array, value, i, x);
+    }
+};
+
+// 20. Write a recursive version of map.
+// rMap([1,2,3], timesTwo); // [2,4,6]
+var rMap = function (array, callback, i = 0, newArr = []) {
+    if (i === array.length) { return newArr; }
+    newArr.push(callback(array[i]));
+    i++;
+    return rMap(array, callback, i, newArr);
+};
+
+// 21. Write a function that counts the number of times a key occurs in an object.
+// var testobj = {'e': {'x':'y'}, 't':{'r': {'e':'r'}, 'p': {'y':'r'}},'y':'e'};
+// countKeysInObj(testobj, 'r') // 1
+// countKeysInObj(testobj, 'e') // 2
+var countKeysInObj = function (obj, key) {
+};
+
+// 22. Write a function that counts the number of times a value occurs in an object.
+// var testobj = {'e': {'x':'y'}, 't':{'r': {'e':'r'}, 'p': {'y':'r'}},'y':'e'};
+// countValuesInObj(testobj, 'r') // 2
+// countValuesInObj(testobj, 'e') // 1
+var countValuesInObj = function (obj, value) {
+};
+
+// 23. Find all keys in an object (and nested objects) by a provided name and rename
+// them to a provided new name while preserving the value stored at that key.
+var replaceKeysInObj = function (obj, key, newKey) {
+};
+
+// 24. Get the first n Fibonacci numbers.  In the Fibonacci Sequence, each subsequent
+// number is the sum of the previous two.
+// Example:  0, 1, 1, 2, 3, 5, 8, 13, 21, 34.....
+// fibonacci(5);  // [0, 1, 1, 2, 3, 5]
+// Note:  The 0 is not counted.
+var fibonacci = function (n) {
+};
+
+// 25. Return the Fibonacci number located at index n of the Fibonacci sequence.
+// [0,1,1,2,3,5,8,13,21]
+// nthFibo(5); // 5
+// nthFibo(7); // 13
+// nthFibo(3); // 2
+var nthFibo = function (n, i = 0, array = [0, 1]) {
+    if (i === n) { return array[i]; }
+    if (n < 0) { return null; }
+    array.push(array[i] + array[i + 1]);
+    i++;
+    return nthFibo(n, i, array)
+};
+
+// 26. Given an array of words, return a new array containing each word capitalized.
+// var words = ['i', 'am', 'learning', 'recursion'];
+// capitalizedWords(words); // ['I', 'AM', 'LEARNING', 'RECURSION']
+var capitalizeWords = function (input, array = [], i = 0) {
+    if (input.length === array.length) { return array; }
+    array.push(input[i].toUpperCase());
+    i++;
+    return capitalizeWords(input, array, i);
+}
+
+// 27. Given an array of strings, capitalize the first letter of each index.
+// capitalizeFirst(['car', 'poop', 'banana']); // ['Car', 'Poop', 'Banana']
+var capitalizeFirst = function (array, newArr = [], i = 0) {
+    if (array.length === newArr.length) { return newArr; }
+    newArr.push(array[i].charAt(0).toUpperCase() + array[i].slice(1));
+    i++;
+    return capitalizeFirst(array, newArr, i);
+};
+
+// 28. Return the sum of all even numbers in an object containing nested objects.
+// var obj1 = {
+//   a: 2,
+//   b: {b: 2, bb: {b: 3, bb: {b: 2}}},
+//   c: {c: {c: 2}, cc: 'ball', ccc: 5},
+//   d: 1,
+//   e: {e: {e: 2}, ee: 'car'}
+// };
+// nestedEvenSum(obj1); // 10
+var nestedEvenSum = function (obj) {
+};
+
+// 29. Flatten an array containing nested arrays.
+// Example: flatten([1,[2],[3,[[4]]],5]); // [1,2,3,4,5]
+var flatten = function (arrays) {
+};
+
+// 30. Given a string, return an object containing tallies of each letter.
+// letterTally('potato'); // {'p':1, 'o':2, 't':2, 'a':1}
+var letterTally = function (str, obj = {}, i = 0) {
+    if (i === str.length) { return obj; }
+    if (isNaN(obj[str[i]])) {
+        obj[str[i]] = 0;
+    }
+    obj[str[i]] += 1;
+    i++;
+    return letterTally(str, obj, i);
+};
+
+
+
+// 31. Eliminate consecutive duplicates in a list.  If the list contains repeated
+// elements they should be replaced with a single copy of the element. The order of the
+// elements should not be changed.
+// Example: compress([1, 2, 2, 3, 4, 4, 5, 5, 5]) // [1, 2, 3, 4, 5]
+// Example: compress([1, 2, 2, 3, 4, 4, 2, 5, 5, 5, 4, 4]) // [1, 2, 3, 4, 2, 5, 4]
+var compress = function (list, arr = [], i = 0) {
+    if (i === list.length) { return arr; }
+    if (list[i] != arr[arr.length - 1]) {
+        arr.push(list[i]);
+    }
+    i++;
+    return compress(list, arr, i);
+};
+
+// 32. Augment every element in a list with a new value where each element is an array
+// itself.
+// Example: augmentElements([[],[3],[7]], 5); // [[5],[3,5],[7,5]]
+var augmentElements = function (array, aug) {
+};
+
+// 33. Reduce a series of zeroes to a single 0.
+// minimizeZeroes([2,0,0,0,1,4]) // [2,0,1,4]
+// minimizeZeroes([2,0,0,0,1,0,0,4]) // [2,0,1,0,4]
+var minimizeZeroes = function (array, arr = [], i = 0) {
+    if (i === array.length) { return arr; }
+    if (array[i] !== 0) {
+        arr.push(array[i]);
+    } else if (array[i] === 0 && arr[arr.length - 1] != 0) {
+        arr.push(array[i]);
+    }
+    i++;
+    return minimizeZeroes(array, arr, i);
+};
+
+// 34. Alternate the numbers in an array between positive and negative regardless of
+// their original sign.  The first number in the index always needs to be positive.
+// alternateSign([2,7,8,3,1,4]) // [2,-7,8,-3,1,-4]
+// alternateSign([-2,-7,8,3,-1,4]) // [2,-7,8,-3,1,-4]
+var alternateSign = function (array, newArr = [], i = 0, sign = 1) {
+    if (array.length === newArr.length) { return newArr; }
+    newArr.push(array[i]);
+    if (newArr[i] > 0) {
+        newArr[i] *= sign;
+        i++;
+        return alternateSign(array, newArr, i, -sign);
+    } else if (newArr[i] === 0) {
+        i++;
+        return alternateSign(array, newArr, i, -sign);
+    } else {
+        newArr[i] *= -sign;
+        i++;
+        return alternateSign(array, newArr, i, -sign);
+    }
+};
+
+// 35. Given a string, return a string with digits converted to their word equivalent.
+// Assume all numbers are single digits (less than 10).
+// numToText("I have 5 dogs and 6 ponies"); // "I have five dogs and six ponies"
+var numToText = function (str) {
+};
+
+// *** EXTRA CREDIT ***
+
+// 36. Return the number of times a tag occurs in the DOM.
+var tagCount = function (tag, node) {
+};
+
+// 37. Write a function for binary search.
+// Sample array:  [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
+// console.log(binarySearch(5)) will return '5'
+
+var binarySearch = function (array, target, min, max) {
+};
+
+// 38. Write a merge sort function.
+// Sample array:  [34,7,23,32,5,62]
+// Sample output: [5,7,23,32,34,62]
+var mergeSort = function (array) {
+};
+
+
+
+//-----------------------------------
+// DON'T REMOVE THIS CODE -----------
+//-----------------------------------
+
+if ((typeof process !== 'undefined') &&
+    (typeof process.versions.node !== 'undefined')) {
+    module.exports = {
+        factorial,
+        sum,
+        isEven,
+        sumBelow,
+        range,
+        exponent,
+        powerOfTwo,
+        reverse,
+        palindrome,
+        multiply,
+        compareStr,
+        createArray,
+        reverseArr,
+        buildList,
+        countOccurrence,
+        rMap,
+        nthFibo,
+        capitalizeWords,
+        capitalizeFirst,
+        letterTally,
+        compress,
+        minimizeZeroes,
+        alternateSign,
+    };
+}
+
+//-----------------------------------
\ No newline at end of file

From 83f8812206b3b50d370be7109de3c4d4269e0655 Mon Sep 17 00:00:00 2001
From: Half Day <halfday@Mac-mini-2.local>
Date: Thu, 1 Nov 2018 13:58:47 -0500
Subject: [PATCH 7/7] finished recursion (sorry i was late)

---
 .DS_Store        | Bin 0 -> 6148 bytes
 recursion.js     | 464 -----------------------------------------------
 src/recursion.js |  74 ++++----
 3 files changed, 42 insertions(+), 496 deletions(-)
 create mode 100644 .DS_Store
 delete mode 100644 recursion.js

diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 0000000000000000000000000000000000000000..add8e05d3b544664bb51b8e0885c34a31c398e7d
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diff --git a/recursion.js b/recursion.js
deleted file mode 100644
index e876a0557..000000000
--- a/recursion.js
+++ /dev/null
@@ -1,464 +0,0 @@
-// Solve all of the following prompts using recursion.
-
-// 1. Calculate the factorial of a number.  The factorial of a non-negative integer n,
-// denoted by n!, is the product of all positive integers less than or equal to n.
-// Example:  5! = 5 x 4 x 3 x 2 x 1 = 120
-// factorial(5);  // 120
-var factorial = function (n, sum = 1, i = n) {
-    if (n < 0) { return null; }
-    if (i === 0) { return sum; }
-    sum *= i;
-    i--;
-    return factorial(n - 1, sum);
-};
-
-// 2. Compute the sum of an array of integers.
-// Example:  sum([1, 2, 3, 4, 5, 6]);  // 21
-var sum = function (array, total = 0, i = 0) {
-    if (i >= array.length) {
-        return total;
-    }
-    total += array[i];
-    i++;
-    return sum(array, total, i);
-};
-
-// 3. Sum all numbers in an array containing nested arrays.
-// Example: arraySum([1,[2,3],[[4]],5]); // 15
-var arraySum = function (array) {
-
-};
-
-// 4. Check if a number is even.
-var isEven = function (n, i = n) {
-    if (i - 2 === 0) {
-        return boolean = true;
-    } else if (i - 2 > 0) {
-        i -= 2;
-        boolean = false;
-        return isEven(n, i, boolean);
-    } else if (i + 2 === 0) {
-        return boolean = true;
-    } else if (i + 2 < 0) {
-        i += 2;
-        boolean = false;
-        return isEven(n, i, boolean);
-    }
-    return boolean;
-};
-
-// 5. Sum all integers below a given integer.
-// sumBelow(10); // 45
-// sumBelow(7); // 21
-var sumBelow = function (n, sum = 0, i = n) {
-    if (n === 0) { return sum; }
-    if (n > 0) {
-        i = n - 1;
-        sum += i;
-        i--;
-        return sumBelow(n - 1, sum, i);
-    } else if (n < 0) {
-        i = n + 1;
-        sum += i;
-        i++;
-        return sumBelow(n + 1, sum, i);
-    }
-    return sum;
-};
-
-// 6. Get the integers in range (x, y).
-// Example:  range(2, 9);  // [3, 4, 5, 6, 7, 8]
-var range = function (x, y, arr = []) {
-    if (x === y) { return arr; }
-    if (x > y) {
-        if (y !== x - 1) {
-            x--;
-            arr.push(x);
-            return range(x, y, arr);
-        }
-        return arr; 0.
-    }
-    if (x !== y - 1) {
-        x++;
-        arr.push(x);
-        return range(x, y, arr);
-    }
-    return arr;
-};
-
-// 7. Compute the exponent of a number.
-// The exponent of a number says how many times the base number is used as a factor.
-// 8^2 = 8 x 8 = 64.  Here, 8 is the base and 2 is the exponent.
-// Example:  exponent(4,3);  // 64
-// https://www.khanacademy.org/computing/computer-science/algorithms/recursive-algorithms/a/computing-powers-of-a-number
-var exponent = function (base, exp, i = exp, total = 1) {
-    if (exp === 0) { return 1; }
-    if (exp === 1) { return base; }
-    if (i === 0) { return total; }
-    if (i > 0) {
-        total *= base;
-        i--;
-        return exponent(base, exp, i, total);
-    }
-    if (i < 0) {
-        total /= base;
-        i++;
-        return exponent(base, exp, i, total);
-    }
-    return total;
-};
-
-// 8. Determine if a number is a power of two.
-// powerOfTwo(1); // true
-// powerOfTwo(16); // true
-// powerOfTwo(10); // false
-var powerOfTwo = function (n, x = 1) {
-    if (x === n) { return true; }
-    if (x > n) { return false; }
-    if (x < n) {
-        x *= 2;
-        return powerOfTwo(n, x);
-    }
-};
-
-// 9. Write a function that accepts a string a reverses it.
-var reverse = function (string) {
-    if (string === "") { return ""; }
-    else {
-        return reverse(string.substr(1)) + string.charAt(0);
-    }
-};
-
-// 10. Write a function that determines if a string is a palindrome.
-var palindrome = function (string, i = string.length - 1, back = "") {
-    string = string.replace(" ", "");
-    back = back.replace(" ", "");
-    if (i < 0) {
-        if (back.toLowerCase() == string.toLowerCase()) {
-            return true;
-        } else {
-            return false;
-        }
-    }
-    back = back.concat(string.charAt(i));
-    i--;
-    return palindrome(string, i, back);
-};
-
-// 11. Write a function that returns the remainder of x divided by y without using the
-// modulo (%) operator.
-// modulo(5,2) // 1
-// modulo(17,5) // 2
-// modulo(22,6) // 4
-var modulo = function (x, y) {
-};
-
-// 12. Write a function that multiplies two numbers without using the * operator  or
-// JavaScript's Math object.
-var multiply = function (x, y, i = y, total = 0) {
-    if (x === 0 || y === 0) { return 0; }
-    if (i === 0 && y > 0) { return total; }
-    if (i === 0 && y < 0) { return -total; }
-    if (y > 0) {
-        total += x;
-        i--;
-        return multiply(x, y, i, total);
-    }
-    if (y < 0) {
-        total += x;
-        i++;
-        return multiply(x, y, i, total);
-    }
-};
-
-// 13. Write a function that divides two numbers without using the / operator  or
-// JavaScript's Math object.
-var divide = function (x, y) {
-};
-
-// 14. Find the greatest common divisor (gcd) of two positive numbers.  The GCD of two
-// integers is the greatest integer that divides both x and y with no remainder.
-// Example:  gcd(4,36);  // 4
-// http://www.cse.wustl.edu/~kjg/cse131/Notes/Recursion/recursion.html
-// https://www.khanacademy.org/computing/computer-science/cryptography/modarithmetic/a/the-euclidean-algorithm
-var gcd = function (x, y) {
-};
-
-// 15. Write a function that compares each character of two strings and returns true if
-// both are identical.
-// compareStr('house', 'houses') // false
-// compareStr('', '') // true
-// compareStr('tomato', 'tomato') // true
-var compareStr = function (str1, str2, i = 0) {
-    if (i === str1.length && i === str2.length) { return true; }
-    if (str1.charAt(i) !== str2.charAt(i)) {
-        return false;
-    } else if (str1.charAt(i) === str2.charAt(i)) {
-        i++;
-        return compareStr(str1, str2, i);
-    }
-    return true;
-};
-
-// 16. Write a function that accepts a string and creates an array where each letter
-// occupies an index of the array.
-var createArray = function (string, i = 0, array = []) {
-    if (i === string.length) { return array; }
-    if (string.charAt(i)) {
-        array.push(string.charAt(i));
-        i++;
-        return createArray(string, i, array);
-    }
-    return array;
-};
-
-// 17. Reverse the order of an array
-var reverseArr = function (array, i = array.length - 1, newArr = []) {
-    if (i === -1) { return newArr; }
-    if (i >= 0) {
-        newArr.push(array[i]);
-        i--;
-        return reverseArr(array, i, newArr);
-    }
-};
-
-// 18. Create a new array with a given value and length.
-// buildList(0,5) // [0,0,0,0,0]
-// buildList(7,3) // [7,7,7]
-var buildList = function (value, length, i = 0, array = []) {
-    if (i === length) { return array; }
-    array.push(value);
-    i++;
-    return buildList(value, length, i, array);
-};
-
-// 19. Count the occurence of a value inside a list.
-// countOccurrence([2,7,4,4,1,4], 4) // 3
-// countOccurrence([2,'banana',4,4,1,'banana'], 'banana') // 2
-var countOccurrence = function (array, value, i = 0, x = 0) {
-    if (i === array.length) { return x; }
-    if (array[i] === value) {
-        i++;
-        x++;
-        return countOccurrence(array, value, i, x);
-    } else {
-        i++;
-        return countOccurrence(array, value, i, x);
-    }
-};
-
-// 20. Write a recursive version of map.
-// rMap([1,2,3], timesTwo); // [2,4,6]
-var rMap = function (array, callback, i = 0, newArr = []) {
-    if (i === array.length) { return newArr; }
-    newArr.push(callback(array[i]));
-    i++;
-    return rMap(array, callback, i, newArr);
-};
-
-// 21. Write a function that counts the number of times a key occurs in an object.
-// var testobj = {'e': {'x':'y'}, 't':{'r': {'e':'r'}, 'p': {'y':'r'}},'y':'e'};
-// countKeysInObj(testobj, 'r') // 1
-// countKeysInObj(testobj, 'e') // 2
-var countKeysInObj = function (obj, key) {
-};
-
-// 22. Write a function that counts the number of times a value occurs in an object.
-// var testobj = {'e': {'x':'y'}, 't':{'r': {'e':'r'}, 'p': {'y':'r'}},'y':'e'};
-// countValuesInObj(testobj, 'r') // 2
-// countValuesInObj(testobj, 'e') // 1
-var countValuesInObj = function (obj, value) {
-};
-
-// 23. Find all keys in an object (and nested objects) by a provided name and rename
-// them to a provided new name while preserving the value stored at that key.
-var replaceKeysInObj = function (obj, key, newKey) {
-};
-
-// 24. Get the first n Fibonacci numbers.  In the Fibonacci Sequence, each subsequent
-// number is the sum of the previous two.
-// Example:  0, 1, 1, 2, 3, 5, 8, 13, 21, 34.....
-// fibonacci(5);  // [0, 1, 1, 2, 3, 5]
-// Note:  The 0 is not counted.
-var fibonacci = function (n) {
-};
-
-// 25. Return the Fibonacci number located at index n of the Fibonacci sequence.
-// [0,1,1,2,3,5,8,13,21]
-// nthFibo(5); // 5
-// nthFibo(7); // 13
-// nthFibo(3); // 2
-var nthFibo = function (n, i = 0, array = [0, 1]) {
-    if (i === n) { return array[i]; }
-    if (n < 0) { return null; }
-    array.push(array[i] + array[i + 1]);
-    i++;
-    return nthFibo(n, i, array)
-};
-
-// 26. Given an array of words, return a new array containing each word capitalized.
-// var words = ['i', 'am', 'learning', 'recursion'];
-// capitalizedWords(words); // ['I', 'AM', 'LEARNING', 'RECURSION']
-var capitalizeWords = function (input, array = [], i = 0) {
-    if (input.length === array.length) { return array; }
-    array.push(input[i].toUpperCase());
-    i++;
-    return capitalizeWords(input, array, i);
-}
-
-// 27. Given an array of strings, capitalize the first letter of each index.
-// capitalizeFirst(['car', 'poop', 'banana']); // ['Car', 'Poop', 'Banana']
-var capitalizeFirst = function (array, newArr = [], i = 0) {
-    if (array.length === newArr.length) { return newArr; }
-    newArr.push(array[i].charAt(0).toUpperCase() + array[i].slice(1));
-    i++;
-    return capitalizeFirst(array, newArr, i);
-};
-
-// 28. Return the sum of all even numbers in an object containing nested objects.
-// var obj1 = {
-//   a: 2,
-//   b: {b: 2, bb: {b: 3, bb: {b: 2}}},
-//   c: {c: {c: 2}, cc: 'ball', ccc: 5},
-//   d: 1,
-//   e: {e: {e: 2}, ee: 'car'}
-// };
-// nestedEvenSum(obj1); // 10
-var nestedEvenSum = function (obj) {
-};
-
-// 29. Flatten an array containing nested arrays.
-// Example: flatten([1,[2],[3,[[4]]],5]); // [1,2,3,4,5]
-var flatten = function (arrays) {
-};
-
-// 30. Given a string, return an object containing tallies of each letter.
-// letterTally('potato'); // {'p':1, 'o':2, 't':2, 'a':1}
-var letterTally = function (str, obj = {}, i = 0) {
-    if (i === str.length) { return obj; }
-    if (isNaN(obj[str[i]])) {
-        obj[str[i]] = 0;
-    }
-    obj[str[i]] += 1;
-    i++;
-    return letterTally(str, obj, i);
-};
-
-
-
-// 31. Eliminate consecutive duplicates in a list.  If the list contains repeated
-// elements they should be replaced with a single copy of the element. The order of the
-// elements should not be changed.
-// Example: compress([1, 2, 2, 3, 4, 4, 5, 5, 5]) // [1, 2, 3, 4, 5]
-// Example: compress([1, 2, 2, 3, 4, 4, 2, 5, 5, 5, 4, 4]) // [1, 2, 3, 4, 2, 5, 4]
-var compress = function (list, arr = [], i = 0) {
-    if (i === list.length) { return arr; }
-    if (list[i] != arr[arr.length - 1]) {
-        arr.push(list[i]);
-    }
-    i++;
-    return compress(list, arr, i);
-};
-
-// 32. Augment every element in a list with a new value where each element is an array
-// itself.
-// Example: augmentElements([[],[3],[7]], 5); // [[5],[3,5],[7,5]]
-var augmentElements = function (array, aug) {
-};
-
-// 33. Reduce a series of zeroes to a single 0.
-// minimizeZeroes([2,0,0,0,1,4]) // [2,0,1,4]
-// minimizeZeroes([2,0,0,0,1,0,0,4]) // [2,0,1,0,4]
-var minimizeZeroes = function (array, arr = [], i = 0) {
-    if (i === array.length) { return arr; }
-    if (array[i] !== 0) {
-        arr.push(array[i]);
-    } else if (array[i] === 0 && arr[arr.length - 1] != 0) {
-        arr.push(array[i]);
-    }
-    i++;
-    return minimizeZeroes(array, arr, i);
-};
-
-// 34. Alternate the numbers in an array between positive and negative regardless of
-// their original sign.  The first number in the index always needs to be positive.
-// alternateSign([2,7,8,3,1,4]) // [2,-7,8,-3,1,-4]
-// alternateSign([-2,-7,8,3,-1,4]) // [2,-7,8,-3,1,-4]
-var alternateSign = function (array, newArr = [], i = 0, sign = 1) {
-    if (array.length === newArr.length) { return newArr; }
-    newArr.push(array[i]);
-    if (newArr[i] > 0) {
-        newArr[i] *= sign;
-        i++;
-        return alternateSign(array, newArr, i, -sign);
-    } else if (newArr[i] === 0) {
-        i++;
-        return alternateSign(array, newArr, i, -sign);
-    } else {
-        newArr[i] *= -sign;
-        i++;
-        return alternateSign(array, newArr, i, -sign);
-    }
-};
-
-// 35. Given a string, return a string with digits converted to their word equivalent.
-// Assume all numbers are single digits (less than 10).
-// numToText("I have 5 dogs and 6 ponies"); // "I have five dogs and six ponies"
-var numToText = function (str) {
-};
-
-// *** EXTRA CREDIT ***
-
-// 36. Return the number of times a tag occurs in the DOM.
-var tagCount = function (tag, node) {
-};
-
-// 37. Write a function for binary search.
-// Sample array:  [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
-// console.log(binarySearch(5)) will return '5'
-
-var binarySearch = function (array, target, min, max) {
-};
-
-// 38. Write a merge sort function.
-// Sample array:  [34,7,23,32,5,62]
-// Sample output: [5,7,23,32,34,62]
-var mergeSort = function (array) {
-};
-
-
-
-//-----------------------------------
-// DON'T REMOVE THIS CODE -----------
-//-----------------------------------
-
-if ((typeof process !== 'undefined') &&
-    (typeof process.versions.node !== 'undefined')) {
-    module.exports = {
-        factorial,
-        sum,
-        isEven,
-        sumBelow,
-        range,
-        exponent,
-        powerOfTwo,
-        reverse,
-        palindrome,
-        multiply,
-        compareStr,
-        createArray,
-        reverseArr,
-        buildList,
-        countOccurrence,
-        rMap,
-        nthFibo,
-        capitalizeWords,
-        capitalizeFirst,
-        letterTally,
-        compress,
-        minimizeZeroes,
-        alternateSign,
-    };
-}
-
-//-----------------------------------
\ No newline at end of file
diff --git a/src/recursion.js b/src/recursion.js
index 62c4d9a66..7d5bb202c 100644
--- a/src/recursion.js
+++ b/src/recursion.js
@@ -130,21 +130,15 @@ var reverse = function (string) {
 };
 
 // 10. Write a function that determines if a string is a palindrome.
-var palindrome = function (string, boolean = false, reverseString = function (string) {
-    if (string === "") { return ""; }
-    else { return reverseString(string.substr(1)) + string.charAt(0); }
-}, i = 0) {
-
-    if (string.charAt(0) === reverseString(string).charAt(0 + i)) {
-        i++;
-        return palindrome(string.slice(1));
-    } else if (string.charAt(0) !== reverseString(string).charAt(0)) {
-        return true;
+var palindrome = function (string) {
+    if (string.length <= 1) { return true; }
+    if (string[0].toLowerCase() !== string[string.length - 1].toLowerCase()) {
+        return false;
     }
-    // [1, 2, 3, 4, 5, 6]
-    // i = 0;
-    // x = string.length - (i + 1);
-};
+    string = string.substr(1, string.length - 2);
+    string = string.replace(' ', '');
+    return palindrome(string);
+}
 
 // 11. Write a function that returns the remainder of x divided by y without using the
 // modulo (%) operator.
@@ -335,30 +329,29 @@ var flatten = function (arrays) {
 
 // 30. Given a string, return an object containing tallies of each letter.
 // letterTally('potato'); // {'p':1, 'o':2, 't':2, 'a':1}
-var letterTally = function (string, object = {}, array = [], i = 0, key = array[i]) {
-    if (i === string.length) { return object; }
-    if (string.length > array.length) {
-        array.push(string.charAt(i));
-        i++;
-        return letterTally(string, object, array, i, array[i]);
-    }
-
-    if (array.length === string.length) {
-        i = 0;
-        object[key] = countOccurrence(array, array[i], i);
-        return letterTally(string, object, array, i, array[i]);
+var letterTally = function (str, obj = {}, tally = 0, i = 0) {
+    let letters = str.split('');
+    let arrOfObjKeys = Object.keys(obj);
+    if (i === letters.length) { return obj; }
+    if (!obj[letters[i]]) { obj[letters[i]] = 1; }
+    else {
+        obj[letters[i]] += 1;
     }
-
-return object;
-
+    i++;
+    return letterTally(str, obj, tally, i);
 };
 
+
 // 31. Eliminate consecutive duplicates in a list.  If the list contains repeated
 // elements they should be replaced with a single copy of the element. The order of the
 // elements should not be changed.
 // Example: compress([1, 2, 2, 3, 4, 4, 5, 5, 5]) // [1, 2, 3, 4, 5]
 // Example: compress([1, 2, 2, 3, 4, 4, 2, 5, 5, 5, 4, 4]) // [1, 2, 3, 4, 2, 5, 4]
-var compress = function (list) {
+var compress = function (list, arr = [], i = 0) {
+    if (i === list.length) { return arr; }
+    if (list[i] !== arr[arr.length - 1]) { arr.push(list[i]); }
+    i++;
+    return compress(list, arr, i);
 };
 
 // 32. Augment every element in a list with a new value where each element is an array
@@ -370,14 +363,31 @@ var augmentElements = function (array, aug) {
 // 33. Reduce a series of zeroes to a single 0.
 // minimizeZeroes([2,0,0,0,1,4]) // [2,0,1,4]
 // minimizeZeroes([2,0,0,0,1,0,0,4]) // [2,0,1,0,4]
-var minimizeZeroes = function (array) {
+var minimizeZeroes = function(array, arr = [], i= 0, n =1) {
+    if(i === array.length){
+        return arr;
+    }
+    if(array[i] !== array[n]){
+        arr.push(array[i]);
+    }    
+    i++;
+    n++;
+    return minimizeZeroes(array, arr, i , n)
 };
 
+
 // 34. Alternate the numbers in an array between positive and negative regardless of
 // their original sign.  The first number in the index always needs to be positive.
 // alternateSign([2,7,8,3,1,4]) // [2,-7,8,-3,1,-4]
 // alternateSign([-2,-7,8,3,-1,4]) // [2,-7,8,-3,1,-4]
-var alternateSign = function (array, i = 1, newArr = [array[0]]) {
+var alternateSign = function (array, i = 0) {
+    i++;
+    var el = array[i];
+    if (i === array.length) { return array; }
+    if (array[0] < 0) { array[0] *= -1; }
+    if (el > 0 && i % 2 === 1) { array[i] = array[i] * -1; }
+    if (el < 0 && i % 2 === 0) { array[i] *= -1; }
+    return alternateSign(array, i);
 };
 
 // 35. Given a string, return a string with digits converted to their word equivalent.