代码

#include <iostream>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int tmp, n = 500000;
    for(int i = 1; i <= n; ++i) cin >> tmp;
    for(int i = 1; i <= n; ++i) cout << tmp << tmp;
    return 0;
}

评测结果