题都有套路的wdds 写了： 2025年 1月 24日 18:25 你考过几次？ 光是读懂题目就要5分钟，今天第一题就做不出
The problem requires us to count the number of "good" subsequences in a given string s. To qualify as good, a subsequence must not be empty and all characters within the subsequence should appear with the same frequency. For example, in the string "aabbcc", the subsequences "abc", "aabbcc", and "bbcc" are considered good because each letter appears with the same frequency within those subsequences.
Since the number of good subsequences could be quite large, we calculate the answer modulo (10^9 + 7), which is a commonly used prime number for modulo operations in computational problems to avoid integer overflow.
Note that a subsequence can be obtained by deleting some or no characters from a string without changing the order of the remaining characters. It does not need to be a contiguous section of the string.
总结一下，就那么些套路
跟鸡阿姨一样，多练多总结就行了。
