Submission #331680

#	Time	Username	Problem	Language	Result	Execution time	Memory
331680		Blagojce	Tents (JOI18_tents)	C++11	100 / 100	82 ms	70764 KiB

tents

#include <bits/stdc++.h> 
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define rfr(i, n, m) for(int i = (n); i >= (m); i --)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x), end(x)
#include <time.h>
#include <cmath>
 
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
const int i_inf = 1e9;
const ll inf = 2e18;
const ll mod = 1e9+7;
const ld eps = 1e-13;
const ld pi  = 3.14159265359;
const int mxn = 5e5;
mt19937 _rand(time(NULL));
clock_t z;

int main(){
	int n, m;
	cin >> n >> m;
	ll dp[n+1][m+1];
	memset(dp, 0, sizeof(dp));
	fr(i, 0, n+1) dp[i][0] = 1;
	fr(i, 0, m+1) dp[0][i] = 1;
	
	fr(i, 1, n+1){
		fr(j, 1, m+1){
			dp[i][j] = dp[i-1][j];
			if(j >= 2) dp[i][j] += dp[i-1][j-2]*j*(j-1)/2;
			if(i >= 2) dp[i][j] += dp[i-2][j-1]*j*(i-1);
			dp[i][j] += j*dp[i-1][j-1]*4;
			dp[i][j] %= mod;
		}
	}
	ll ans = (dp[n][m]-1+mod)%mod;
	cout<<ans<<endl;
}

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