Submission #306951

#	Time	Username	Problem	Language	Result	Execution time	Memory
306951		vipghn2003	Tents (JOI18_tents)	C++14	0 / 100	1 ms	384 KiB

tents

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

const int N=3005;
const int mod=1e9+7;
int n,m,dp[N][N];

main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cin>>n>>m;
    for(int j=0;j<=m;j++) dp[0][j]=1;
    for(int j=0;j<=n;j++) dp[j][0]=1;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            dp[i][j]=(dp[i-1][j]+dp[i-1][j-1]*m*4)%mod;
            if(j>=2) dp[i][j]=(dp[i][j]+dp[i-1][j-2]*m*(m-1)/2)%mod;
            if(i>=2) dp[i][j]=(dp[i][j]+dp[i-2][j-1]*m*(n-1))%mod;
        }
    }
    cout<<(dp[n][m]-1+mod)%mod;
}

Compilation message (stderr)

tents.cpp:9:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
    9 | main()
      |      ^

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