1093 Count PAT's (25 分)

1093 Count PAT’s (25 分)

解題思想

AC代碼

#include <iostream>
#include <cstdio>
#include <string>
using namespace std;
int main(){
    string ori;
    cin >> ori;
    int countt = 0, countp = 0, ret = 0;
    for (int i = 0; i < ori.length(); i++)
        if (ori[i] == 'T') countt++;
    for (int i = 0; i < ori.length(); i++){
        if (ori[i] == 'P') countp++;
        else if (ori[i] == 'T') countt--;
        else if (ori[i] == 'A')
            ret = (ret+(countp*countt)%1000000007)%1000000007;
    }
    printf("%d", ret);
}