Submission #68675

#	Time	Username	Problem	Language	Result	Execution time	Memory
68675		IvanC	Tents (JOI18_tents)	C++17	100 / 100	312 ms	71920 KiB

tents

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

typedef long long ll;

const int MAXN = 3010;
const int MOD = 1e9 + 7;

ll escolhe2(ll x){
	return (x * (x-1))/2;
}

ll dp[MAXN][MAXN];
int H,W;

ll solve(int a,int b){

	if(a < 0 || b < 0) return 0;
	if(a == 0 || b == 0) return 1;
	if(dp[a][b] != -1) return dp[a][b];

	ll qtd = solve(a-1,b);
	qtd += solve(a - 1,b - 2)*escolhe2(b);
	qtd += 4*solve(a-1,b-1)*b;
	qtd += solve(a - 2,b - 1)*b*(a-1);
	if(a == H && b == W) qtd--;

	qtd %= MOD;

	return dp[a][b] = qtd;

}

int main(){

	memset(dp,-1,sizeof(dp));
	cin >> H >> W;
	cout << solve(H,W) << endl;

	return 0;
}

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