Submission #353535

#	Time	Username	Problem	Language	Result	Execution time	Memory
353535		shivensinha4	Tents (JOI18_tents)	C++17	48 / 100	659 ms	213740 KiB

tents

#include "bits/stdc++.h"
using namespace std;
#define for_(i, s, e) for (int i = s; i < (int) e; i++)
#define for__(i, s, e) for (ll i = s; i < e; i++)
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
#define endl '\n'

const ll mod = 1e9+7;

ll ncr(ll n, ll r) {
	if (r == 0) return 1;
	if (r == 1) return n;
	if (r == 2) return ((n*(n-1))/2 % mod);
	assert(false);
}

int main() {
#ifdef mlocal
	freopen("test.in", "r", stdin);
#endif
	
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	int n, m; cin >> n >> m;
	ll dp[n+1][m+1][m+1]; // [row][empty][light]
	memset(dp, 0, sizeof(dp));
	
	vector<ll> tp(m+1);
	tp[0] = 1;
	for_(i, 1, tp.size()) tp[i] = (4*tp[i-1]) % mod;
	for_(i, 0, m+1) for_(j, 0, m+1) if (j+i <= m) dp[n][i][j] = tp[j];
	for (int i = n-1;  i >= 0; i--) {
//		cout << i << ": " << endl;
		for_(emp, 0, m+1) for_(lt, 0, m+1) if (emp+lt <= m) {
			for_(empTake, 0, min(emp, 2)+1) for_(ltTake, 0, min(lt, 1)+1) {
				if ((ltTake and empTake)) continue;
				dp[i][emp][lt] += (((ncr(emp, empTake) * ncr(lt, ltTake)) % mod) * dp[i+1][emp-empTake][lt-ltTake+(empTake == 2 ? 0 : empTake)]) % mod;
				if (dp[i][emp][lt] >= mod) dp[i][emp][lt] -= mod;
			}
//			cout << "empty: " << emp << " light: " << lt << " -> " << dp[i][emp][lt] << endl;
		}
	}
	
	cout << (dp[0][m][0]-1+mod) % mod << endl;
	
	
	return 0;
}

• Subtask 1: 48 / 48
• Subtask 2: 0 / 52