Submission #49057

#	Time	Username	Problem	Language	Result	Execution time	Memory
49057		Namnamseo	Tents (JOI18_tents)	C++17	100 / 100	668 ms	63996 KiB

tents

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

ll dp[3010][3010];

const ll mod = 1'000'000'007;

ll f(ll w, ll h){
	if(!w || !h) return 1;
	if(w<0 || h<0) return 0;
	if(dp[w][h]) return dp[w][h];
	ll ret = 0;
	ret += f(w, h-1);
	(ret += w * 4 * f(w-1, h-1) % mod) %= mod;
	(ret += w*(w-1)/2 % mod * f(w-2, h-1) % mod) %= mod;
	(ret += w * (h-1) % mod * f(w-1, h-2) % mod) %= mod;
	return dp[w][h]=ret;
}

int main()
{
	int n, m; cin >> n >> m;
	cout << (f(n, m) + mod - 1) % mod << endl;
	return 0;
}

• Subtask 1: 48 / 48
• Subtask 2: 52 / 52