Submission #228045

#	Time	Username	Problem	Language	Result	Execution time	Memory
228045		bharat2002	Tents (JOI18_tents)	C++14	100 / 100	313 ms	71672 KiB

tents

/*input
1 2
*/
#include<bits/stdc++.h>
using namespace std;
const int N=3011;
const int mod=1e9+7;
#define int long long
const int inf=1e18;
#define pii pair<int, int>
#define f first
#define s second 
#define mp make_pair
#define FOR(i, n) for(int i=1;i<=n;i++)
#define TRACE(x) cerr << #x << " = " << x << endl 
//Trace prints the name of the variable and the value.
int dp[N][N];
int solve(int r, int c)
{
	if(r<0||c<0) return 0;
	if(r==0||c==0) return 1;
	if(dp[r][c]!=-1) return dp[r][c];
	int temp=solve(r, c-1);
	temp+=(((r*(r-1))/2)*solve(r-2, c-1))%mod;temp%=mod;
	temp+=(4*r*solve(r-1, c-1))%mod;temp%=mod;
	temp+=((c-1)*r*solve(r-1, c-2));temp%=mod;
	dp[r][c]=temp;return dp[r][c];
}
signed main()
{
	ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	int r, c;cin>>r>>c;
	for(int i=0;i<N;i++)
		for(int j=0;j<N;j++) dp[i][j]=-1;
	cout<<(solve(r, c)+mod-1)%mod;
}

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