【題解】ZeroJudge a159: 11743 – Credit Check

#include <iostream>
using namespace std;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int T;
    cin >> T;
    while (T--){
        int n, sum1 = 0, sum2 = 0;
        for (int i = 0; i < 4; i++){
            cin >> n;
            for (int j = 3; j >= 0; j--){
                if (j % 2){
                    sum2 += n % 10;
                } else {
                    int x = 2 * (n % 10);
                    sum1 += (x/10) + (x%10);
                }
                n /= 10;
            }
        }
        if ((sum1 + sum2) % 10) cout << "Invalid\n";
        else cout << "Valid\n";
    }
    return 0;
}