Given a string, find a prefix with the highest frequency. If two prefixes have the same frequency then consider the one with maximum length.
Input : str = "abc" Output : abc Each prefix has same frequency(one) and the prefix with maximum length is "abc". Input : str = "abcab" Output : ab Both prefix "a" and "ab" occur two times and the prefix with maximum length is "ab".
The idea is to observe that every prefix of the given string will contain the first character of the string in it and the first character alone is also a prefix of the given string. So the prefix with the highest occurrence is the first character. The task now remains to maximize the length of the highest frequency prefix.
- Take a vector which will store the indices of the first element of the string.
- If the first element appeared only once, then the longest prefix will be the whole string.
- Otherwise, loop till the second appearance of the first element and check one letter after every stored index.
- If there is no mismatch we move forward otherwise we stop.
Below is the implementation of the above approach:
Time Complexity : O(N)
- Print the longest prefix of the given string which is also the suffix of the same string
- Longest string in an array which matches with prefix of the given string
- Longest sub-string having frequency of each character less than equal to k
- Find the longest common prefix between two strings after performing swaps on second string
- Longest prefix which is also suffix
- Longest Common Prefix using Trie
- Longest Common Prefix Matching | Set-6
- Longest prefix that contains same number of X and Y in an array
- Find minimum shift for longest common prefix
- Count subarrays where second highest lie before highest
- Sub-strings of a string that are prefix of the same string
- Longest Common Prefix using Character by Character Matching
- Longest Common Prefix using Word by Word Matching
- Frequency of a substring in a string
- Python program to print the substrings that are prefix of the given string
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