Submission #147316

#	Time	Username	Problem	Language	Result	Execution time	Memory
147316		mosiashvililuka	Tents (JOI18_tents)	C++14	100 / 100	249 ms	71132 KiB

tents

#include<bits/stdc++.h>
using namespace std;
long long a,b,c,d,e,dp[3009][3009],mod=1000000007;
int main(){
	ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
	cin>>a>>b;
	for(c=0; c<=a+1; c++){
		for(d=0; d<=b+1; d++){
			dp[c][d]=1;
		}
	}
	for(c=1; c<=a; c++){
		for(d=1; d<=b; d++){
			dp[c][d]=c*dp[c-1][d-1]*4+dp[c][d-1];
			if(d>1) dp[c][d]+=c*(d-1)*dp[c-1][d-2];
			if(c>=2) dp[c][d]+=(c-1)*c/2*dp[c-2][d-1];
			dp[c][d]%=mod;
		}
	}
	cout<<(dp[a][b]-1+mod)%mod;
	return 0;
}

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