1093. Count PAT's (25)

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    string s;
    cin >> s;
    long long sum = 0, p = 0, t = 0;
    for (int i = 0; i < s.length(); i++) {
        if(s[i] == 'T') t++;
    }
    for (int i = 0; i < s.length(); i++) {
        if(s[i] == 'P') p++;
        if(s[i] == 'T') t--;
        if(s[i] == 'A') sum =  (sum + p * t % 1000000007) % 1000000007;
    }

    cout << sum  << endl;
    return 0;
}