#P10816. [EC Final 2020] Namomo Subsequence
[EC Final 2020] Namomo Subsequence
题目描述
gshfd1jkhaRaadfglkjerVcvuy0gf said Prof. Pang.
To understand Prof. Pang's word, we would like to calculate the number of s of it. The word by Prof. Pang is a string  with  characters where each character is either an English letter (lower or upper case) or a digit. The -th character of  is denoted by  (). A subsequence  of  is defined by a list of indices  such that . Let  be a function on two characters such that  when  and  otherwise.  is a namomo subsequence of  if and only if for any , $compare(s[t_i], s[t_j]) = compare(namomo[i], namomo[j])$, where  represents the -th character of the string namomo ().
Output the number of namomo subsequences of a given string modulo .
输入格式
The first line contains a string  with  characters ().  contains only lower case English letters (a -- z), upper case English letters (A -- Z) and digits (0 -- 9).
输出格式
Output one integer -- the answer modulo .
wohaha
1
momomo
0
gshfd1jkhaRaadfglkjerVcvuy0gf
73
retiredMiFaFa0v0
33
