Submission #1077645

#	Time	Username	Problem	Language	Result	Execution time	Memory
1077645		boyan2010	Tents (JOI18_tents)	C++17	100 / 100	224 ms	67676 KiB

tents

#include<bits/stdc++.h>
using namespace std;
long long n,m,dp[3001][3001];
bool vis[3001][3001];
const long long mod=1e9+7;
long long f(long long i,long long j)
{
    if(j==0 || i==0)
    {
        return 1;
    }
    if(i<0 || j<0)
    {
        return 0;
    }
    if(vis[i][j])
    {
        return dp[i][j];
    }
    vis[i][j]=1;
    dp[i][j]=((((f(i-1,j)+4*j*f(i-1,j-1))%mod+f(i-1,j-2)*j*(j-1)/2)%mod)+f(i-2,j-1)*j*(i-1))%mod;
    return dp[i][j];
}
int main()
{
    cin>>n>>m;
    cout<<f(n,m)-1;
    return 0;
}

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