[etc] 백준 11575 Affine Cipher

https://www.acmicpc.net/problem/11575

#include <iostream>
using namespace std;
 
int main(){
    ios_base::sync_with_stdio(false);
    int a,b,T;
    string s;
    
    cin >> T;
    
    while(T--){
        cin >> a >> b;
        cin >> s;
        for(int i = 0; i < s.size(); i++){
            cout << char((((a*(s[i]-65)) + b) %26)+65);
        }
        cout << endl;
    }
}