Submission #1022267

#	Time	Username	Problem	Language	Result	Execution time	Memory
1022267		gvancak	Tents (JOI18_tents)	C++11	100 / 100	94 ms	70996 KiB

tents

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

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