Submission #950879

#	Time	Username	Problem	Language	Result	Execution time	Memory
950879		Soshi85	Tents (JOI18_tents)	C++17	100 / 100	59 ms	70992 KiB

tents

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")//,bmi,bmi2,lzcnt,popcnt
#include<bits/stdc++.h>

using namespace std;
using ll = long long;
using pii = pair<ll, ll>;
using piii = pair<ll, pii>;

#define pb              push_back
#define F               first
#define S               second
#define len(x)          (int)x.size()
#define all(x)          x.begin(),x.end()
#define file            freopen("connect.in", "r", stdin);freopen("connect.out", "w", stdout);
#define kill(x)         {cout << x << '\n'; continue;}
#define int             long long
	
const int maxn = 3e3 + 5, maxm = 2e5, LG = 20, MOD = 1e9+7;// 998244353
const ll inf =  6e18;

//priority_queue< int, vector<int>, greater<int>> pq;  min heap
//priority_queue< int, vector<int>,  less<int> > pq;   max heap

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

int h, w, dp[maxn][maxn];
signed main() {
	ios::sync_with_stdio(0), cin.tie(0);
	
	cin >> h >> w;
	
	for(int i = 0; i <= h; ++i) dp[i][0] = 1;
	for(int i = 0; i <= w; ++i) dp[0][i] = 1;

	dp[1][1] = 5;
	for(int i = 2; i <= max(h, w); ++i) {
		dp[1][i] = 4 + i-1 + dp[1][i-1];
		dp[1][i] %= MOD;
		dp[i][1] = dp[1][i];
	}

	for(int i = 2; i <= h; ++i)
		for(int j = 2; j <= w; ++j) {
			dp[i][j] = (4 * j * dp[i-1][j-1] % MOD);
			dp[i][j] += ((j*(j-1)/2 % MOD) * dp[i-1][j-2] % MOD) % MOD;
			dp[i][j] += ((j*(i-1)  % MOD) * dp[i-2][j-1] % MOD) % MOD;
			dp[i][j] += dp[i-1][j];
			dp[i][j] %= MOD;
		}

	cout << dp[h][w] - 1;
}
// it was fun while it lasted
// ctrl + d

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