_482.java

package com.fishercoder.solutions;

/**
 * 482. License Key Formatting
 *
 * Now you are given a string S, which represents a software license key which we would like to format.
 * The string S is composed of alphanumerical characters and dashes.
 * The dashes split the alphanumerical characters within the string into groups.
 * (i.e. if there are m dashes, the string is split into m+1 groups).
 * The dashes in the given string are possibly misplaced.
 * We want each group of characters to be of length K
 * (except for possibly the first group, which could be shorter, but still must contain at least one character).
 * To satisfy this requirement, we will reinsert dashes. Additionally, all the lower case letters in the string must be converted to upper case.
 * So, you are given a non-empty string S, representing a license key to format, and an integer K.
 * And you need to return the license key formatted according to the description above.

 Example 1:
 Input: S = "2-4A0r7-4k", K = 4
 Output: "24A0-R74K"
 Explanation: The string S has been split into two parts, each part has 4 characters.

 Example 2:
 Input: S = "2-4A0r7-4k", K = 3
 Output: "24-A0R-74K"
 Explanation: The string S has been split into three parts, each part has 3 characters except the first part as it could be shorter as said above.

 Note:
 The length of string S will not exceed 12,000, and K is a positive integer.
 String S consists only of alphanumerical characters (a-z and/or A-Z and/or 0-9) and dashes(-).
 String S is non-empty.
 */
public class _482 {
    public static class Solution1 {
        public String licenseKeyFormatting(String S, int K) {
            StringBuilder stringBuilder = new StringBuilder();
            char[] SChars = S.toCharArray();
            for (int i = S.length() - 1, j = 0; i >= 0; ) {
                if (j < K) {
                    if (SChars[i] != '-') {
                        if (SChars[i] >= 'a' && SChars[i] <= 'z') {
                            stringBuilder.append(Character.toUpperCase(SChars[i]));
                        } else {
                            stringBuilder.append(SChars[i]);
                        }
                        j++;
                    }
                    i--;
                } else if (j == K) {
                    j = 0;
                    stringBuilder.append('-');
                }
            }
            if (stringBuilder.length() > 1 && stringBuilder.substring(stringBuilder.length() - 1).equals("-")) {
                return stringBuilder.reverse().substring(1);
            }
            return stringBuilder.reverse().toString();
        }
    }
}