Submission #1077677

#	Time	Username	Problem	Language	Result	Execution time	Memory
1077677		rado	Tents (JOI18_tents)	C++14	100 / 100	52 ms	70740 KiB

tents

#include <bits/stdc++.h>
using namespace std;

void fastIO(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int MOD = 1e9+7;
long long dp[3001][3001];

int main(){
    fastIO();
    int n, m; cin>>n>>m;
    for(int i=0; i<=n; i++)dp[i][0] = 1;
    for(int j=0; j<=m; j++)dp[0][j] = 1;
    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            dp[i][j] = dp[i-1][j] + 4*j*dp[i-1][j-1];
            if(j >= 2)dp[i][j] += dp[i-1][j-2]*j*(j-1)/2;
            if(i >= 2)dp[i][j] += dp[i-2][j-1]*j*(i-1);
            dp[i][j] %= MOD;
        }
    }
    cout<<dp[n][m]-1<<endl;
}

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