Submission #33996

#	Time	Username	Problem	Language	Result	Execution time	Memory
33996		aome	마스코트 (JOI13_mascots)	C++14	100 / 100	106 ms	37472 KiB

mascots

#include <bits/stdc++.h>
using namespace std;

const int N = 3005;
const int mod = 1e9 + 7;

int n, m, q, res = 1;
int prd[N], inv[N];
int f[N][N];
int mnX, mxX, mnY, mxY;
int lenX, lenY;

int pw(int x, int y) {
	if (!y) return 1;
	int ret = pw(x, y >> 1); ret = 1LL * ret * ret % mod;
	if (y & 1) ret = 1LL * ret * x % mod; return ret;
}

int C(int n, int k) {
	if (n < k) return 0;
	return 1LL * prd[n] * inv[n - k] % mod * inv[k] % mod;
}

int main() {
	ios::sync_with_stdio(false);
	cin >> n >> m >> q;
	prd[0] = inv[0] = 1;
	for (int i = 1; i < N; ++i) {
		prd[i] = 1LL * prd[i - 1] * i % mod, inv[i] = pw(prd[i], mod - 2);
	}
	mnX = mnY = 1e9;
	for (int i = 1; i <= q; ++i) {
		int x, y; cin >> x >> y;
		mnX = min(mnX, x), mnY = min(mnY, y);
		mxX = max(mxX, x), mxY = max(mxY, y);
	}
	lenX = mxX - mnX + 1, lenY = mxY - mnY + 1;
	int cntIn = lenX * lenY - q;
	for (int i = 1; i <= cntIn; ++i) res = 1LL * res * i % mod;
	f[lenX][lenY] = 1;
	for (int i = lenX; i <= n; ++i) {
		for (int j = lenY; j <= m; ++j) {
			if (i == lenX && j == lenY) continue;
			if (i != lenX) f[i][j] = (f[i][j] + 1LL * f[i - 1][j] * prd[j]) % mod;
			if (j != lenY) f[i][j] = (f[i][j] + 1LL * f[i][j - 1] * prd[i]) % mod;
		}
	}
	res = 1LL * res * f[n][m] % mod;
	res = 1LL * res * C(n - lenX, n - mxX) % mod * C(m - lenY, m - mxY) % mod;
	cout << res;
}

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60