Submission #746493

#	Time	Username	Problem	Language	Result	Execution time	Memory
746493		Sami_Massah	Tents (JOI18_tents)	C++17	100 / 100	87 ms	71008 KiB

tents

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


const long long maxn = 3e3 + 12, mod = 1e9 + 7, inf = 1e9 + 12 ;
long long n, m, dp[maxn][maxn];
int main(){
    cin >> n >> m;
    dp[0][0] = 1;
    for(int i = 1; i <= n; i++)
        dp[i][0] = 1;
    for(int j = 1; j <= m; j++)
        dp[0][j] = 1;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++){
            dp[i][j] += dp[i][j - 1];
            dp[i][j] += i * dp[i - 1][j - 1] * 4;

            if(j >= 2)
                dp[i][j] += i * (j - 1) * dp[i - 1][j - 2];
            if(i >= 2)
                dp[i][j] += (i * (i - 1) / 2) * dp[i - 2][j - 1];
            dp[i][j] %= mod;
        //    cout << i << ' ' << j << ' ' << dp[i][j] << endl;
        }
    cout << (dp[n][m] - 1 + mod * 2) % mod << endl;


}

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