Suppose substring s appears x times in string S, then substring s2 of substring s will appear at least x times, or more
A single character does not count, so here comes the problem. One of the substrings that appears most often must be a 2-character substring
If you just want to find any one that meets the conditions, you only need to find a 2-character substring
If you want to find all the substrings with the number of occurrences = the maximum number of occurrences, it will be a little more complicated.
1. Assume that the length of the string S is N 2. Combine the two adjacent characters in the string into N-1 substrings, and then count the 2-character byte strings to see which one appears the most. 3. If there is no 2-character string with an equal number greater than 1, the search ends 4. If there are multiple 2-character strings with equal times greater than 1, then compare these 2-character strings to see if there is the end of the first string Is equal to the string at the beginning of the second string. For example, ab appears 3 times and bc appears 3 times. Then abc may appear multiple times. If this happens, determine the number of occurrences of the 3-character string. If the number Less than the number of occurrences of a 2-character string, then the answer is a 2-character string, otherwise it may be a 3-character string. 5. Then continue to detect 4, 5, and 6 character strings
In addition, we need to clarify the statistical algorithm for the number of occurrences of a string. For example, does the substring aa in aaaaaa appear 3 times or 5 times?
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Suppose substring s appears x times in string S, then substring s2 of substring s will appear at least x times, or more
A single character does not count, so here comes the problem. One of the substrings that appears most often must be a 2-character substring
If you just want to find any one that meets the conditions, you only need to find a 2-character substring
If you want to find all the substrings with the number of occurrences = the maximum number of occurrences, it will be a little more complicated.
1. Assume that the length of the string S is N
2. Combine the two adjacent characters in the string into N-1 substrings, and then count the 2-character byte strings to see which one appears the most.
3. If there is no 2-character string with an equal number greater than 1, the search ends
4. If there are multiple 2-character strings with equal times greater than 1, then compare these 2-character strings to see if there is the end of the first string Is equal to the string at the beginning of the second string. For example, ab appears 3 times and bc appears 3 times. Then abc may appear multiple times. If this happens, determine the number of occurrences of the 3-character string. If the number Less than the number of occurrences of a 2-character string, then the answer is a 2-character string, otherwise it may be a 3-character string.
5. Then continue to detect 4, 5, and 6 character strings
In addition, we need to clarify the statistical algorithm for the number of occurrences of a string. For example, does the substring aa in aaaaaa appear 3 times or 5 times?
It feels a little easier to get regular. If you don’t use regular expressions, it will definitely need to be solved iteratively or recursively