Submission

Score: 100

User: winkawin2552

Problemset: ตรวจบัตรเครดิต

Language: c

Time: 0.002 second

Submitted On: 2025-10-10 10:31:08

#include <stdio.h>

int cal_sum(int size, char word[]){
    int sum = 0;
    for(int i = 0; i< size ; i++){
        if(i %2==0){
            int check = (word[size-i-1] - '0') *2;
            if(check >=10) sum+= check /10 + check %10;
            else sum+= check;
        }else sum +=word[size-i-1]- '0';
    } return sum;
}

int main() {
    char num[17];
    scanf("%s", num);
    char keep = num[15];
    int n = cal_sum(15, num);
    if(((10 - (n % 10)) %10) == (keep-'0')) printf("yes");
    else printf("no");

    return 0;
}