oj.uz

Submission #716691

# Submission time Handle Problem Language Result Execution time Memory
716691 2023-03-30T19:38:12 Z Sohsoh84 Tents (JOI18_tents) C++17
100 / 100
 288 ms 71380 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pll;

#define all(x)			(x).begin(),(x).end()
#define X			first
#define Y			second
#define sep			' '
#define endl			'\n'
#define debug(x)		cerr << #x << ": " <<  x << endl;

const ll MAXN = 3e3 + 10;
const ll MOD = 1e9 + 7;
const ll INV2 = (MOD + 1) / 2;

inline ll poww(ll a, ll b) {
	ll ans = 1;
	while (b) {
		if (b & 1) ans = ans * a % MOD;
		b >>= 1;
		a = a * a % MOD;
	}

	return ans;
}

ll fact[MAXN], inv[MAXN], n, m, dp[MAXN][MAXN];;

inline ll C(ll k, ll n) {
	if (k < 0 || k > n) return 0;
	return fact[n] * inv[k] % MOD * inv[n - k] % MOD;
}

inline ll calc(ll n, ll m, ll k) {
	return C(k, n) * C(2 * k, m) % MOD * fact[2 * k] % MOD * poww(INV2, k) % MOD;
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	ll ans = 0;
	fact[0] = inv[0] = 1;
	for (int i = 1; i < MAXN; i++) {
		fact[i] = fact[i - 1] * i % MOD;
		inv[i] = poww(fact[i], MOD - 2);
	}

	for (int i = 0; i < MAXN; i++) {
		for (int j = 0; j < MAXN; j++) {
			if (i == 0 || j == 0) {
				dp[i][j] = 1;
				continue;
			}

			dp[i][j] = (dp[i - 1][j] + dp[i - 1][j - 1] * j * 4) % MOD;
		}
	}

	cin >> n >> m;
	for (int i = 0; i <= n; i++) {
		for (int j = 0; 2 * i + j <= m && i + 2 * j <= n; j++) {
			ll tans = calc(n, m, i) * calc(m - 2 * i, n - i, j) % MOD * dp[n - i - 2 * j][m - 2 * i - j] % MOD;
			ans = (ans + tans) % MOD;
		}
	}

	cout << (ans + MOD - 1) % MOD << endl;
	return 0;
}

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 71244 KB Output is correct
2 Correct 58 ms 71256 KB Output is correct
3 Correct 44 ms 71296 KB Output is correct
4 Correct 43 ms 71264 KB Output is correct
5 Correct 42 ms 71200 KB Output is correct
6 Correct 51 ms 71204 KB Output is correct
7 Correct 46 ms 71200 KB Output is correct
8 Correct 46 ms 71268 KB Output is correct
9 Correct 43 ms 71168 KB Output is correct
10 Correct 44 ms 71224 KB Output is correct
11 Correct 46 ms 71244 KB Output is correct
12 Correct 51 ms 71140 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 71244 KB Output is correct
2 Correct 58 ms 71256 KB Output is correct
3 Correct 44 ms 71296 KB Output is correct
4 Correct 43 ms 71264 KB Output is correct
5 Correct 42 ms 71200 KB Output is correct
6 Correct 51 ms 71204 KB Output is correct
7 Correct 46 ms 71200 KB Output is correct
8 Correct 46 ms 71268 KB Output is correct
9 Correct 43 ms 71168 KB Output is correct
10 Correct 44 ms 71224 KB Output is correct
11 Correct 46 ms 71244 KB Output is correct
12 Correct 51 ms 71140 KB Output is correct
13 Correct 65 ms 71228 KB Output is correct
14 Correct 47 ms 71168 KB Output is correct
15 Correct 159 ms 71272 KB Output is correct
16 Correct 46 ms 71224 KB Output is correct
17 Correct 57 ms 71244 KB Output is correct
18 Correct 72 ms 71264 KB Output is correct
19 Correct 189 ms 71220 KB Output is correct
20 Correct 171 ms 71264 KB Output is correct
21 Correct 109 ms 71252 KB Output is correct
22 Correct 118 ms 71380 KB Output is correct
23 Correct 55 ms 71276 KB Output is correct
24 Correct 288 ms 71264 KB Output is correct
25 Correct 198 ms 71276 KB Output is correct
26 Correct 223 ms 71372 KB Output is correct
27 Correct 261 ms 71344 KB Output is correct