#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;
using vvi = vector<vector<int>>;
using vvl = vector<vector<ll>>;

#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define mp make_pair
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((int)(x).size())
#define endl '\n'

const int INF = 1e9 + 7;
const ll LINF = 1e18 + 9, MOD = 1e9 + 7;
const ld EPS = 1e-9;

void fileIO()
{
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
#endif
}

void solve()
{
    // write your code here
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);

    fileIO();

    int t = 1;
    // cin >> t;

    for (int tc = 1; tc <= t; tc++)
    {
        solve();
    }

    return 0;
}

60 linesutf-8

$cat explanation_notes.md

notes_viewer --renderedmarkdown (math enabled)

CP Starter Template

Paste at the top of every solution to skip boilerplate.

What's Included

Fast I/O — ios_base::sync_with_stdio(false) + cin.tie(nullptr) for ~2x faster input

Type aliases — ll for long long, pii for pair, vi/vll for vectors

Macros — all(x) / rall(x) for range iterators, pb for push_back, sz(x) for safe size cast

Constants — two common mods (

998244353

and

10^9 + 7

), MAXN for array sizing

solve() — empty function where contest logic goes

Notes

cout.tie(nullptr) is optional — only helps if mixing cout and cin heavily

MAXN is set to

2 \times 10^5 + 5

by default — adjust per problem

Some contests need int main() to call solve() in a loop for multi-test — add that as needed