CF1791D.Distinct Split
普及/提高-
通过率:0%
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题目描述
Let's denote the f(x) function for a string x as the number of distinct characters that the string contains. For example f(abc)=3 , f(bbbbb)=1 , and f(babacaba)=3 .
Given a string s , split it into two non-empty strings a and b such that f(a)+f(b) is the maximum possible. In other words, find the maximum possible value of f(a)+f(b) such that a+b=s (the concatenation of string a and string b is equal to string s ).
输入格式
The input consists of multiple test cases. The first line contains an integer t ( 1≤t≤104 ) — the number of test cases. The description of the test cases follows.
The first line of each test case contains an integer n ( 2≤n≤2⋅105 ) — the length of the string s .
The second line contains the string s , consisting of lowercase English letters.
It is guaranteed that the sum of n over all test cases does not exceed 2⋅105 .
输出格式
For each test case, output a single integer — the maximum possible value of f(a)+f(b) such that a+b=s .
输入输出样例
输入#1
5 2 aa 7 abcabcd 5 aaaaa 10 paiumoment 4 aazz
输出#1
2 7 2 10 3
说明/提示
For the first test case, there is only one valid way to split aa into two non-empty strings a and a , and f(a)+f(a)=1+1=2 .
For the second test case, by splitting abcabcd into abc and abcd we can get the answer of f(abc)+f(abcd)=3+4=7 which is maximum possible.
For the third test case, it doesn't matter how we split the string, the answer will always be 2 .