Submission #288148

#	Time	Username	Problem	Language	Result	Execution time	Memory
288148		ngotienhung	Tents (JOI18_tents)	C++14	100 / 100	216 ms	70904 KiB

tents

#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second

using namespace std;

const int maxN = 3005;
const int mod = 1e9 + 7;

int n,m;
int f[maxN][maxN];

int32_t main()
{
	ios_base::sync_with_stdio(false); cin.tie(); cout.tie();

    cin >> m >> n;

    for(int i = 0; i <= m; ++i)
        f[i][0] = 1;
    for(int i = 0; i <= n; ++i)
        f[0][i] = 1;

    for(int i = 1; i <= m; ++i){
        for(int j = 1; j <= n; ++j){
            f[i][j] = (f[i][j] + f[i - 1][j]) % mod;
            f[i][j] = (f[i][j] + f[i - 1][j - 1] * 4 % mod * j % mod) % mod;
            if(j >= 2)
            f[i][j] = (f[i][j] + f[i - 1][j - 2] * (j*(j - 1)/2 % mod)) % mod;
            if(i >= 2)
            f[i][j] = (f[i][j] + f[i - 2][j - 1] * j % mod * (i - 1) % mod) % mod;
        }
    }

    cout << (f[m][n] - 1 + mod) % mod;
}

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