Submission

Score: 100

User: blaboo123

Problemset: ตรวจบัตรเครดิต

Language: cpp

Time: 0.004 second

Submitted On: 2026-10-06 14:12:24

#include <bits/stdc++.h>
using namespace std ;

int main() {
    ios_base::sync_with_stdio(0) ;
    cin.tie(0) ;
    // input 16 digits credit card
    string s ;
    cin >> s ;
    int n = s.length() ;
    int ld = s[n-1] - '0' ;
    s.pop_back() ;
    n = s.length() ;
    reverse(s.begin(),s.end()) ;
    int sum = 0 ;
    for (int i = 0 ; i < n ; i += 2){
        int k = (s[i] - '0') * 2 ;
        if (k >= 10){
            sum += (k / 10) ;
            sum += (k % 10) ;
        }
        else {
            sum += k ;
        }
    }
    for (int i = 1 ; i < n ; i += 2){
        sum += s[i] - '0' ;
    }
    if ((10 - (sum % 10)) % 10 == ld){
        cout << "yes\n" ;
    }
    else {
        cout << "no\n" ;
    }
    return 0 ;
}