From 2017.8~
g++ -std=c++11 -O2 -fsanitize=undefined -Wall -Wextra -Wshadow -o %<.o %
#include <bits/stdc++.h>
using namespace std;
const int M=int(1e9)+7;
int a[int(1e5)+5];
// Global variables here
int main() {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
// Main program here
}
}