Submission #331391

#	Time	Username	Problem	Language	Result	Execution time	Memory
331391		GioChkhaidze	Tents (JOI18_tents)	C++14	100 / 100	319 ms	70892 KiB

tents

#include <bits/stdc++.h>

#define ll long long

using namespace std;

const int N=3003;

ll n,m,dp[N][N],mod=1e9+7;

main () {
	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++) {
			if (1<=i) dp[i][j]=(dp[i][j]+dp[i-1][j])%mod;
			if (1<=i && 1<=j) dp[i][j]=(dp[i][j]+j*dp[i-1][j-1]*4)%mod;
			if (2<=i && 1<=j) dp[i][j]=(dp[i][j]+j*(i-1)*dp[i-2][j-1])%mod;
			if (1<=i && 2<=j) dp[i][j]=(dp[i][j]+((j-1)*j/2)*dp[i-1][j-2])%mod;
		}
	
	cout<<(dp[n][m]-1+mod)%mod<<"\n";
}

Compilation message (stderr)

tents.cpp:11:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   11 | main () {
      |       ^

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