这不GESP三级题吗？

#include<bits/stdc++.h>
using namespace std;
char ch;
string s;
int a[11], k, num;
int main() {
    cin >> s;
    a[1] = int(s[0] - 48);
    a[2] = int(s[2] - 48);
    a[3] = int(s[3] - 48);
    a[4] = int(s[4] - 48);
    a[5] = int(s[6] - 48);
    a[6] = int(s[7] - 48);
    a[7] = int(s[8] - 48);
    a[8] = int(s[9] - 48);
    a[9] = int(s[10] - 48);
    for (int i = 1; i <= 9; i++) num += a[i] * i;
    for (int i = 1; i <= 9; i++) {
        if (num % 11 == 10) ch = 'X';
        else ch = char(num % 11 + 48);
    }
    if (ch == s[12]) cout << "Right";
    else {
        for (int i = 0; i < s.size() - 1; i++) cout << s[i];
        cout << ch;
    }
    return 0;
}