Submission #140542

#	Time	Username	Problem	Language	Result	Execution time	Memory
140542		Mahmoud_Adel	Tents (JOI18_tents)	C++14	100 / 100	143 ms	71032 KiB

tents

#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
typedef long long ll;
const int N = 3005, mod = 1e9+7;
int n, m;
ll dp[N][N];
int main()
{
	cin >> n >> m;
	for(int i=0; i<N; i++) dp[i][0] = 1, dp[0][i] = 1;
	for(int i=1; i<=n; i++)
	{
		for(int j=1; j<=m; j++)
		{
			dp[i][j] = 4 * j * dp[i-1][j-1] + dp[i-1][j], dp[i][j] %= mod;
			dp[i][j] += j * (j-1)/2 * dp[i-1][j-2], dp[i][j] %= mod;
			dp[i][j] += (i-1) * j * dp[i-2][j-1], dp[i][j] %= mod;
		}
	}
	cout << dp[n][m]-1 << endl;
}

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