Submission #948890

#	Time	Username	Problem	Language	Result	Execution time	Memory
948890		starchan	Tents (JOI18_tents)	C++17	100 / 100	116 ms	71356 KiB

tents

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define in pair<int, int>
#define f first
#define s second
#define pb push_back
#define pob pop_back
#define INF (int)1e17
#define MX (int)3e5+5
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
const int mod = 1e9+7;
int c2(int j)
{
	return ((j*(j-1))/2)%mod;
}
signed main()
{
	fast();
	int n, m;
	cin >> n >> m;
	int dp[n+10][m+10];
	for(int i = 0; i <= n+9; i++)
		dp[i][0] = 1;
	for(int i = 0; i <= m+9; i++)
		dp[0][i] = 1;
	for(int i = 1; i <= n+9; i++)
		dp[i][1] = (1 + (4*i) + c2(i))%mod;
	for(int i = 1; i <= m+9; i++)
		dp[1][i] = (1 + (4*i) + c2(i))%mod;
	for(int i = 2; i <= n+9; i++)
	{
		for(int j = 2; j <= m+9; j++)
		{
			dp[i][j] = ((dp[i-1][j]%mod)+((4*j*dp[i-1][j-1])%mod)+(c2(j)*dp[i-1][j-2])%mod)%mod;
			dp[i][j]+=(((i-1)*j*dp[i-2][j-1])%mod); dp[i][j]%=mod;
		}
	}
	dp[n][m]+=(mod-1);
	dp[n][m]%=mod;
	cout << dp[n][m] << "\n";
	return 0;
}	

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