杭电5842之Lweb and String

Problem Description Lweb has a string S . Oneday, he decided to transform this string to a new sequence. You need help him determine this transformation to get a sequence which has the longest LIS(Strictly Increasing). You need transform every letter in this string to a new number. A is the set of letters of S , B is the set of natural numbers. Every injection f:A→B can be treat as an legal transformation. For example, a String “aabc”, A={a,b,c} , and you can transform it to “1 1 2 3”, and the LIS of the new sequence is 3. Now help Lweb, find the longest LIS which you can obtain from S . LIS: Longest Increasing Subsequence. (https://en.wikipedia.org/wiki/Longest_increasing_subsequence)   Input The first line of the input contains the only integer T,(1≤T≤20) . Then T lines follow, the i-th line contains a string S only containing the lowercase letters, the length of S will not exceed 105 .   Output For each test case, output a single line "Case #x: y", where x is the case number, starting from 1. And y is the answer.   Sample Input 2 aabcc acdeaa   Sample Output Case #1: 3

Case #2: 4

题意：智障题，统计一个只含小写字母的字符串里有多少种不同的字符

AC代码如下：

#include<iostream> #include <string> using namespace std; int main() { int t,i; int n; int num; int a[26]; int k = 1; string s; cin >> t; while (t--) { for (i = 0; i < 26; i++) { a[i] = 1; } num = 0; cin >> s; n = s.size(); for (i = 0; i < n; i++) { if (a[int(s[i]) - 'a']) { a[s[i] - 'a'] = 0; num++; } } cout<< "Case #"<<k++<<": "<< num << endl; }     return 0; }