Submission #933726

#	Time	Username	Problem	Language	Result	Execution time	Memory
933726		parlimoos	Tents (JOI18_tents)	C++14	100 / 100	40 ms	70708 KiB

tents

//Be Name KHODA
#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
#define pb push_back
#define pp pop_back
#define lb lower_bound
#define ub upper_bound
#define cl clear
#define bg begin
#define arr(x) array<int , x>
#define endl '\n'

const int MOD = int(1e9) + 7;

int n , m;
ll dp[3001][3001];

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

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