Submission #601996

#	Time	Username	Problem	Language	Result	Execution time	Memory
601996		alireza_kaviani	Tents (JOI18_tents)	C++17	100 / 100	68 ms	70904 KiB

tents

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

typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;

#define all(x)      (x).begin(),(x).end()
#define X           first
#define Y           second
#define sep         ' '
#define endl        '\n'
#define SZ(x)       ll(x.size())

const ll MAXN = 3010;
const ll LOG = 22;
const ll INF = 8e18;
const ll MOD = 1e9 + 7; //998244353; //1e9 + 9;

ll n , m , dp[MAXN][MAXN];

int main() {
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

    cin >> n >> m;
    for(int i = 0 ; i <= n ; i++){
        for(int j = 0 ; j <= m ; j++){
            if(i == 0 || j == 0){
                dp[i][j] = 1;
                continue;
            }
            dp[i][j] = dp[i - 1][j];
            dp[i][j] += 4 * j * dp[i - 1][j - 1];
            if(j > 1)   dp[i][j] += j * (j - 1) / 2 * dp[i - 1][j - 2];
            if(i > 1)   dp[i][j] += j * (i - 1) * dp[i - 2][j - 1];
            dp[i][j] %= MOD;
        }
    }
    cout << (dp[n][m] + MOD - 1) % MOD << endl;

    return 0;

}
/*

*/

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