Submission #914379

#	Time	Username	Problem	Language	Result	Execution time	Memory
914379		Andrey	Tents (JOI18_tents)	C++14	100 / 100	73 ms	70748 KiB

tents

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

const long long MOD = 1e9+7;

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

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