Submission #707757

#	Time	Username	Problem	Language	Result	Execution time	Memory
707757		ToroTN	Tents (JOI18_tents)	C++14	100 / 100	392 ms	70876 KiB

tents

#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll n,m,dp[3005][3005],MOD=1e9+7;
int main()
{
    ios_base::sync_with_stdio(0),cin.tie(0);
    cin >> n >> m;
    for(int i=0;i<=n;i++)dp[i][0]=1;
    for(int i=0;i<=m;i++)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-1]*(ll)4*j)%MOD;
            dp[i][j]%=MOD;
            if(j>=2)dp[i][j]+=(dp[i-1][j-2]*((ll)j*(j-1)/2))%MOD;
            dp[i][j]%=MOD;
            if(i>=2)dp[i][j]+=(dp[i-2][j-1]*(ll)(i-1)*j)%MOD;
            dp[i][j]%=MOD;
            dp[i][j]+=dp[i-1][j];
            dp[i][j]%=MOD;
        }
    }
    printf("%lld\n",(dp[n][m]-1+MOD)%MOD);
}

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