Submission

Score: 100

User: theem1502

Problemset: ตรวจบัตรเครดิต

Language: c

Time: 0.002 second

Submitted On: 2025-09-10 22:39:06

#include <stdio.h>



int main() {
    char num[16];
    scanf("%s", &num);
    int lastnumber = num[15];
    char mainnum[15] = {0};
    for (int i = 0; i < 15; i++) {
        mainnum[i] = num[i];
    }    
    int numsum = 0;
    for (int i = 0; i < 15; i++) {
        if (i % 2 == 0) {
            if (mainnum[i] - '0' < 5) {
            int currentdigit = mainnum[i] - '0';
            currentdigit *= 2;
            mainnum[i] = currentdigit + '0';
            }
            else {
            numsum += 1 + ((mainnum[i] - '0' - 5) * 2);
            mainnum[i] = '*';
            }
            
        }

    }

    for (int i = 0; i < 15; i++) {
        if (mainnum[i] <= '9' && mainnum[i] >= '0') {
            numsum += mainnum[i] - '0';
        }
    }



    if (((10 - (numsum % 10)) % 10) == lastnumber - '0') {
        printf("%s", "yes");
    } 
    else {
        printf("%s", "no");
    }

}