Submission #521234

#	Time	Username	Problem	Language	Result	Execution time	Memory
521234		Jasiekstrz	Tents (JOI18_tents)	C++17	100 / 100	70 ms	71004 KiB

tents

#include<bits/stdc++.h>
#define fi first
#define se second
using namespace std;
const int N=3e3;
const int MOD=1e9+7;
long long dp[N+10][N+10];
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int n,m;
	cin>>n>>m;
	for(int i=0;i<=max(n,m);i++)
		dp[i][0]=dp[0][i]=1;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=m;j++)
		{
			dp[i][j]+=dp[i-1][j];
			dp[i][j]+=4*j*dp[i-1][j-1];
			if(j>=2)
				dp[i][j]+=((j*(j-1))/2)*dp[i-1][j-2];
			if(i>=2)
				dp[i][j]+=j*(i-1)*dp[i-2][j-1];
			dp[i][j]%=MOD;
		}
	}
	cout<<(dp[n][m]-1+MOD)%MOD<<"\n";
	return 0;
}

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