Submission #1501288

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Source Code Expand

#include "bits/stdc++.h"
#include <regex>
#define _USE_MATH_DEFINES
#include <math.h>

using namespace std;

#ifndef _DEBUG
#define main_ main
#endif
#define FOR(i,s,e) for (int i = int(s); i < int(e); ++i)
#define REP(i,e) FOR(i,0,e)
#define INF (INT_MAX/2)
#define EPS (1.0e-8)
#define LINF (LONG_MAX/2)

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<bool> vb;
typedef vector<string> vs;

template <typename T>
using keyVal = pair<string, T>;
template<typename T>
bool val_greater(const keyVal<T>& left, const keyVal<T>& right) {
	return left.second > right.second;
}

vs split(string str, char sep) {
	vs v; stringstream ss(str); string t;
	while (getline(ss, t, sep)) v.push_back(t);
	return v;
}

void init_global() {}

const ll MOD = 1e9 + 7;

ll pow_mod(ll a, ll n, ll mod) {
	ll res = 1;
	while (n > 0) {
		if (n & 0x01) {
			res *= a;
			res %= mod;
		}
		a = a*a;
		a %= mod;
		n >>= 1;
	}
	return res;
}

ll combi_mod(ll n, ll k, ll mod=MOD) {
	if (n<0 || k<0 || n < k) return 0;
	if (k == 0) return 1;
	if (k == 1) return n%mod;

	ll nume = 1, denom = 1;
	FOR(i, 1, k + 1) {
		nume *= i;
		nume %= mod;
		denom *= i;
		denom %= mod;
	}
	nume %= mod;
	denom %= mod;
	FOR(i, 1, n - k + 1) {
		nume *= k + i;
		nume %= mod;
		denom *= i;
		denom %= mod;
	}
	nume %= mod;
	denom %= mod;

	ll res = nume * pow_mod(denom, mod - 2, mod);
	res %= mod;
	return res;
}

int main_() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int R, C; cin >> R >> C;
	int X, Y; cin >> X >> Y;
	int D, L; cin >> D >> L;
	
	if (X*Y == D + L) {
		ll ans = combi_mod(X*Y, D);
		ans *= (R - X + 1) * (C - Y + 1);
		ans %= MOD;
		cout << ans << endl;
		return 0;
	}

	ll all = combi_mod(X*Y, D + L);

	ll l = combi_mod((X - 1)*Y, D + L);
	ll r = l;
	ll t = combi_mod(X*(Y - 1), D + L);
	ll b = t;

	ll lt = combi_mod((X - 1)*(Y - 1), D + L);
	ll lb = lt;
	ll rt = lt;
	ll rb = lt;
	ll lr = combi_mod((X - 2)*Y, D + L);
	ll tb = combi_mod(X*(Y - 2), D + L);

	ll lrt = combi_mod((X - 2)*(Y - 1), D + L);
	ll lrb = lrt;
	ll ltb = combi_mod((X - 1)*(Y - 2), D + L);
	ll rtb = ltb;

	ll lrtb = combi_mod((X - 2)*(Y - 2), D + L);

	ll l_r_t_b = l+r+t+b
		- lt - lb - rt- rb - lr - tb
		+ lrt + lrb + ltb + rtb
		- lrtb;
	ll ans = all - l_r_t_b;
	while (ans < 0) ans += MOD;
	ans %= MOD;

	ll num = combi_mod(D + L, L);
	ans *= num;
	ans %= MOD;

	ans *= (R - X + 1) * (C - Y + 1);
	ans %= MOD;

	cout << ans << endl;
	return 0;
}

Submission Info

Judge Result