Given a string and a positive integer d. Some characters may be repeated in the given string. Rearrange characters of the given string such that the same characters become d distance away from each other. Note that there can be many possible rearrangements, the output should be one of the possible rearrangements. If no such arrangement is possible, that should also be reported.
Expected time complexity is O(n) where n is length of input string.
Examples: Input: "abb", d = 2 Output: "bab" Input: "aacbbc", d = 3 Output: "abcabc" Input: "geeksforgeeks", d = 3 Output: egkegkesfesor Input: "aaa", d = 2 Output: Cannot be rearranged
Hint: Alphabet size may be assumed as constant (256) and extra space may be used.
Solution: The idea is to count frequencies of all characters and consider the most frequent character first and place all occurrences of it as close as possible. After the most frequent character is placed, repeat the same process for remaining characters.
1) Let the given string be str and size of string be n
2) Traverse str, store all characters and their frequencies in a Max Heap MH. The value of frequency decides the order in MH, i.e., the most frequent character is at the root of MH.
3) Make all characters of str as ‘