Submission #45815

#	Time	Username	Problem	Language	Result	Execution time	Memory
45815		mraron	Tents (JOI18_tents)	C++14	100 / 100	246 ms	71648 KiB

tents

//Noszály Áron 10o Debreceni Fazekas Mihály Gimnázium

#include<iostream>
#include<vector>
#include<map>
#include<set>
#include<cassert>
#include<cassert>
#include<unordered_map>
#include<unordered_set>
#include<functional>
#include<queue>
#include<stack>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<sstream>
#include<iomanip>
#include<cstdio>
#include<cstdlib>
#include<numeric>
using namespace std;

#define all(x) (x).begin(), (x).end()
#define pb push_back
#define xx first
#define yy second
#define sz(x) (int)(x).size()
#define gc getchar
#define IO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define mp make_pair

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

const double PI=acos(-1);

template<typename T> T getint() {
	T val=0;
	char c;
	
	bool neg=false;
	while((c=gc()) && !(c>='0' && c<='9')) {
		neg|=c=='-';
	}

	do {
		val=(val*10)+c-'0';
	} while((c=gc()) && (c>='0' && c<='9'));

	return val*(neg?-1:1);
}

const ll mod=1e9+7;

ll dp[3001][3001];

ll calc(int i, int j) {
	if(i==0 || j==0) return 1;
	if(dp[i][j]!=-1) return dp[i][j];
	ll ans=0;
	if(i>1) ans=(ans+calc(i-2, j-1)*i*(i-1)/2)%mod;
	ans=(ans+4*calc(i-1,j-1)*i)%mod;
	if(j>1) ans=(ans+calc(i-1,j-2)*i*(j-1))%mod;
	ans=(ans+calc(i,j-1))%mod;
	
	return dp[i][j]=ans;
}


int main() {
	IO;
	memset(dp, -1, sizeof dp);
	int a,b;
	cin>>a>>b;
	cout<<(calc(a,b)-1+mod)%mod<<"\n";
	
	return 0;
}

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