Submission #1161972

#	Time	Username	Problem	Language	Result	Execution time	Memory
1161972		minhpk	Tents (JOI18_tents)	C++20	0 / 100	0 ms	324 KiB

tents

#include <bits/stdc++.h>
#define int long long
using namespace std;
int a,b;
int f[3005][3005];
int mod =1e9+7;
int dp(int i,int j){
    if (i<0 || j<0){
        return 0;
    }
    if (i==0 || j==0){
        return 1;
    }
    if (f[i][j]!=-1){
        return f[i][j];
    }
    f[i][j]=0;
    f[i][j] = (f[i][j] + (dp(i-1,j-2)*j*(j-1)/2 + dp(i-2,j-1)*(i-1)*j)%mod )%mod;
    f[i][j] = (f[i][j]+  (dp(i-1,j-1) + (dp(i-1,j-1)*4*j)%mod))%mod;
    return f[i][j];


}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> a >> b;
    for (int i=1;i<=a;i++){
         for (int j=1;j<=b;j++){
              f[i][j]=-1;
         }
    }
    cout << dp(a,b)-1;
    return 0;
}

• Subtask 1: 0 / 48
• Subtask 2: 0 / 52