Submission

Score: 100

User: jeeno987

Problemset: ตรวจบัตรเครดิต

Language: cpp

Time: 0.004 second

Submitted On: 2026-10-10 18:17:18

#include <iostream>
#include <string>
using namespace std;

int main() {
    string s;
    cin >> s;
    int r = 0;
    for (int k = 0; k < 15; k++) {          // k-th digit of the reversed first 15 digits
        int d = s[14 - k] - '0';
        if (k % 2 == 0) d *= 2;             // reversed positions 1, 3, 5, ... are doubled
        r += d / 10 + d % 10;
    }
    cout << ((10 - r % 10) % 10 == s[15] - '0' ? "yes" : "no") << '\n';
    return 0;
}