From d0601fce9e1ad0a5a676316c82a67cb1aac7b5a3 Mon Sep 17 00:00:00 2001 From: Shaina Beth Date: Sat, 16 Jul 2022 20:28:34 -0700 Subject: [PATCH 1/3] fix linked-list unit tests --- linked_list/linked_list.py | 97 ++++++++++++++++++++++++++++++++------ 1 file changed, 83 insertions(+), 14 deletions(-) diff --git a/linked_list/linked_list.py b/linked_list/linked_list.py index 63993214..86356438 100644 --- a/linked_list/linked_list.py +++ b/linked_list/linked_list.py @@ -1,5 +1,10 @@ # Defines a node in the singly linked list +from email import header +from os import curdir +from socket import AI_PASSIVE + + class Node: def __init__(self, value, next_node = None): @@ -13,31 +18,44 @@ def __init__(self): # returns the value in the first node # returns None if the list is empty - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(1) + # Space Complexity: O(1) def get_first(self): - pass + if self.head == None: + return None + return self.head.value # method to add a new node with the specific data value in the linked list # insert the new node at the beginning of the linked list - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(1) + # Space Complexity: O(1) def add_first(self, value): - pass + new_head = Node(value, self.head) + self.head = new_head # method to find if the linked list contains a node with specified value # returns true if found, false otherwise # Time Complexity: ? # Space Complexity: ? def search(self, value): - pass + cur = self.head + while cur != None: + if cur.value == value: + return True + cur = cur.next + return False # method that returns the length of the singly linked list # Time Complexity: ? # Space Complexity: ? def length(self): - pass + cur = self.head + i = 0 + while cur != None: + cur = cur.next + i += 1 + return i # method that returns the value at a given index in the linked list # index count starts at 0 @@ -45,31 +63,77 @@ def length(self): # Time Complexity: ? # Space Complexity: ? def get_at_index(self, index): - pass + cur = self.head + for i in range(index): + if cur == None: + return None + cur = cur.next + return cur.value + # method that returns the value of the last node in the linked list # returns None if the linked list is empty # Time Complexity: ? # Space Complexity: ? def get_last(self): - pass + if self.head == None: + return None + cur = self.head + prev = None + while cur != None: + prev = cur + cur = cur.next + return prev.value # method that inserts a given value as a new last node in the linked list # Time Complexity: ? # Space Complexity: ? def add_last(self, value): - pass + if self.head == None: + self.head = Node(value, None) + return + cur = self.head + prev = None + while cur != None: + prev = cur + cur = cur.next + prev.next = Node(value, None) + # method to return the max value in the linked list # returns the data value and not the node def find_max(self): - pass + if self.head == None: + return None + cur = self.head + cur_max = cur.value + cur = cur.next + while cur != None: + if cur.value > cur_max: + cur_max = cur.value + cur = cur.next + return cur_max + # method to delete the first node found with specified value # Time Complexity: ? # Space Complexity: ? def delete(self, value): - pass + if self.head == None: + return None + if self.head.value == value: + self.head = self.head.next + + prev = self.head + cur = self.head.next + while cur != None and cur.value != value: + prev = cur + cur = cur.next + + if cur != None: + prev.next = cur.next + + # method to print all the values in the linked list # Time Complexity: ? @@ -89,7 +153,12 @@ def visit(self): # Time Complexity: ? # Space Complexity: ? def reverse(self): - pass + cur = self.head + last_made = None + while cur != None: + last_made = Node(cur.value, last_made) + cur = cur.next + self.head = last_made ## Advanced/ Exercises # returns the value at the middle element in the singly linked list From a6b13ef0c37f7004ebb901e181e2eb3fd3f283db Mon Sep 17 00:00:00 2001 From: Shaina Beth Date: Sat, 16 Jul 2022 20:30:01 -0700 Subject: [PATCH 2/3] remove accidental imports --- linked_list/linked_list.py | 5 ----- 1 file changed, 5 deletions(-) diff --git a/linked_list/linked_list.py b/linked_list/linked_list.py index 86356438..e896c3d7 100644 --- a/linked_list/linked_list.py +++ b/linked_list/linked_list.py @@ -1,10 +1,5 @@ # Defines a node in the singly linked list -from email import header -from os import curdir -from socket import AI_PASSIVE - - class Node: def __init__(self, value, next_node = None): From a2980651a2d6bccd5ea1991fa2e3e5d6718529f1 Mon Sep 17 00:00:00 2001 From: Shaina Beth Date: Sat, 16 Jul 2022 20:31:49 -0700 Subject: [PATCH 3/3] fill in missing complexities --- linked_list/linked_list.py | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/linked_list/linked_list.py b/linked_list/linked_list.py index e896c3d7..3ef3a074 100644 --- a/linked_list/linked_list.py +++ b/linked_list/linked_list.py @@ -31,8 +31,8 @@ def add_first(self, value): # method to find if the linked list contains a node with specified value # returns true if found, false otherwise - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(n) + # Space Complexity: O(1) def search(self, value): cur = self.head while cur != None: @@ -42,8 +42,8 @@ def search(self, value): return False # method that returns the length of the singly linked list - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(n) + # Space Complexity: O(1) def length(self): cur = self.head i = 0 @@ -55,8 +55,8 @@ def length(self): # method that returns the value at a given index in the linked list # index count starts at 0 # returns None if there are fewer nodes in the linked list than the index value - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(n) + # Space Complexity: O(1) def get_at_index(self, index): cur = self.head for i in range(index): @@ -68,8 +68,8 @@ def get_at_index(self, index): # method that returns the value of the last node in the linked list # returns None if the linked list is empty - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(n) + # Space Complexity: O(1) def get_last(self): if self.head == None: return None @@ -81,8 +81,8 @@ def get_last(self): return prev.value # method that inserts a given value as a new last node in the linked list - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(n) + # Space Complexity: O(1) def add_last(self, value): if self.head == None: self.head = Node(value, None) @@ -111,8 +111,8 @@ def find_max(self): # method to delete the first node found with specified value - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(n) + # Space Complexity: O(1) def delete(self, value): if self.head == None: return None @@ -131,8 +131,8 @@ def delete(self, value): # method to print all the values in the linked list - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(n) + # Space Complexity: O(n) def visit(self): helper_list = [] current = self.head @@ -145,8 +145,8 @@ def visit(self): # method to reverse the singly linked list # note: the nodes should be moved and not just the values in the nodes - # Time Complexity: ? - # Space Complexity: ? + # Time Complexity: O(n) + # Space Complexity: O(n) def reverse(self): cur = self.head last_made = None