Đây là template (mẫu) code mình hay sài, các bạn cũng có thể tìm thấy trên codeforces của mình

Salmon1 - Codeforces

/*--------------------------------------------
			Competitive programing
		   Name: Đào Xuân Hoàng Tuấn (Salmon)
	Nothing is impossible, as you as you believe you can do it
			 You can do it!!!
	----------------------------------------------*/

#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>

using namespace std;
// using namespace __gnu_pbds;

#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define Hello_i_am_Salmon 		ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define print_fix 			cout << fixed << setprecision(20);
#define show(x)				cerr << #x << " -> " << x << endl;
#define show3 				cerr << "***" << endl;
#define show2 				cerr << "**" << endl;
#define show1 				cerr << "*" << endl;
#define all(v) 				v.begin(), v.end()
#define sz(t) 				(int) t.size()
#define pb 				push_back
#define se 				second
#define fi 				first
#define el  			endl
#define ed 				'\\n'
#define _ 				" "

void debug_out() {cout << '\\n';}
template <typename Head, typename ...Tail>
void debug_out(Head H, Tail ...T)
{
	cout << H << ' ';
	debug_out(T...);
}
#define fix(...) cout << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__)
const long long N = 1e5+10;
const long long Nn = 1e3+10;
const double PI = atan(1)*4;
const int MOD = 1e9 + 7;
const long long INF = 1e9 + 7ll;

	/* --- you should drink a cup of milk tea before reading my code ---- */

int main()
{
	Hello_i_am_Salmon

	
}
	
		

/* Test case 

*/
	/* My code is very beautiful and artistic */

Giải thích nhanh về template:

// Cac dong define de rut gon code

ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
// Dung de giam thoi gian khi cin, cout

void debug_out() {cout << '\\n';}
template <typename Head, typename ...Tail>
void debug_out(Head H, Tail ...T){
    cout << H << ' ';
    debug_out(T...);
}
#define fix(...) cout << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__)
// Dung de fix bug

// Cac const la cac hang so hay dung