Submission #1034059

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034059		vjudge1	Tents (JOI18_tents)	C++17	100 / 100	132 ms	70736 KiB

tents

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int mod=1e9+7;
int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n,m;
    cin>>n>>m;
    int dp[n+1][m+1];
    memset(dp,0,sizeof(dp));
    for(int j=0;j<=m;j++) dp[0][j]=1;
    for(int i=1;i<=n;i++){
        for(int j=0;j<=m;j++){
            dp[i][j]=dp[i-1][j-1]*4*j%mod;
            dp[i][j]=(dp[i][j]+dp[i-1][j])%mod;
            if(j>1) dp[i][j]=(dp[i][j]+dp[i-1][j-2]*(j*(j-1)/2%mod)%mod)%mod;
            if(i>1) dp[i][j]=(dp[i][j]+dp[i-2][j-1]*j%mod*(i-1)%mod)%mod;
        }
    }
    cout<<(dp[n][m]-1+mod)%mod;
}

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