Submission #135272

#	Time	Username	Problem	Language	Result	Execution time	Memory
135272		mohammedehab2002	Tents (JOI18_tents)	C++11	100 / 100	348 ms	36088 KiB

tents

#include <iostream>
#include <string.h>
using namespace std;
#define mod 1000000007
int dp[3005][3005];
int solve(int n,int m)
{
	if (!n || !m)
	return 1;
	if (dp[n][m]!=-1)
	return dp[n][m];
	int ans=(solve(n-1,m)+4LL*m*solve(n-1,m-1))%mod;
	if (m>=2)
	ans=(ans+1LL*m*(m-1)/2*solve(n-1,m-2))%mod;
	if (n>=2)
	ans=(ans+(n-1LL)*m*solve(n-2,m-1))%mod;
	return dp[n][m]=ans;
}
int main()
{
	int n,m;
	cin >> n >> m;
	memset(dp,-1,sizeof(dp));
	cout << (solve(n,m)-1+mod)%mod;
}

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