Submission #951453

#	Time	Username	Problem	Language	Result	Execution time	Memory
951453		star	Tents (JOI18_tents)	C++14	100 / 100	32 ms	71020 KiB

tents

#include <bits/stdc++.h>
using namespace std;
#define LL long long
#define N 1000000007
LL dp[3005][3005], n, m, i, j;
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    cin >> n >> m;
    for(i=0; i<=3000; i++)
        dp[i][0] = dp[0][i] = 1;
    for(i=1; i<=n; i++)
        for(j=1; j<=m; j++)
        {
            dp[i][j]=dp[i-1][j];
            if (j>=2)dp[i][j]+=(j*(j-1)/2*dp[i-1][j-2]);
            dp[i][j]+=4*j*dp[i-1][j-1];
            if (i>=2)dp[i][j]+=dp[i-2][j-1]*j*(i-1);
            dp[i][j]%=N;
        }

    cout << dp[n][m]-1;
}

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