Submission

Score: 0

User: Darleneee93

Problemset: ตรวจบัตรเครดิต

Language: cpp

Time: 0.005 second

Submitted On: 2026-10-15 13:59:21

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define el << '\n'
#define float double


int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

    string num;
    cin >> num;

    num.pop_back();


    reverse(num.begin(), num.end());

    string number ="";

    for(int i=0;i<num.length();i++){
        int d = num[i] - '0';
        if(i % 2==0){
            d *=2;
        }

        number += to_string(d);
    }

    int ans =0;
    for(int k=0;k<number.length();k++){
        ans += number[k]-'0';
    }

    int final_ans = (10-(ans%10))%10;

    cout << final_ans;
}