Submission #1005439


Source Code Expand

#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if(x < y) x = y; }


template<int MOD>
struct ModInt {
	static const int Mod = MOD;
	unsigned x;
	ModInt() : x(0) {}
	ModInt(signed sig) { int sigt = sig % MOD; if(sigt < 0) sigt += MOD; x = sigt; }
	ModInt(signed long long sig) { int sigt = sig % MOD; if(sigt < 0) sigt += MOD; x = sigt; }
	int get() const { return (int)x; }

	ModInt &operator+=(ModInt that) { if((x += that.x) >= MOD) x -= MOD; return *this; }
	ModInt &operator-=(ModInt that) { if((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
	ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; }
	ModInt &operator/=(ModInt that) { return *this *= that.inverse(); }

	ModInt operator+(ModInt that) const { return ModInt(*this) += that; }
	ModInt operator-(ModInt that) const { return ModInt(*this) -= that; }
	ModInt operator*(ModInt that) const { return ModInt(*this) *= that; }
	ModInt operator/(ModInt that) const { return ModInt(*this) /= that; }

	ModInt inverse() const {
		signed a = x, b = MOD, u = 1, v = 0;
		while(b) {
			signed t = a / b;
			a -= t * b; std::swap(a, b);
			u -= t * v; std::swap(u, v);
		}
		if(u < 0) u += Mod;
		ModInt res; res.x = (unsigned)u;
		return res;
	}
};
typedef ModInt<1000000007> mint;

vector<mint> fact, factinv;
void nCr_computeFactinv(int N) {
	N = min(N, mint::Mod - 1);
	fact.resize(N + 1); factinv.resize(N + 1);
	fact[0] = 1;
	rer(i, 1, N) fact[i] = fact[i - 1] * i;
	factinv[N] = fact[N].inverse();
	for(int i = N; i >= 1; i --) factinv[i - 1] = factinv[i] * i;
}

mint nCr(int n, int r) {
	if(n >= mint::Mod)
		return nCr(n % mint::Mod, r % mint::Mod) * nCr(n / mint::Mod, r / mint::Mod);
	return r > n ? 0 : fact[n] * factinv[n - r] * factinv[r];
}

int main() {
	int N; int A; int B; int C;
	while(~scanf("%d%d%d%d", &N, &A, &B, &C)) {
		nCr_computeFactinv(N);
		mint ans;
		rer(p, 0, N) rer(q, 0, N) {
			int a = A - p, b = B / 2, c = C - p - q * 3;
			if(a < 0 || c < 0 || B % 2 != 0) continue;
			int groups = a + b + p + q;
			mint cnt = 1;
			cnt *= fact[groups];
			cnt *= factinv[a];
			cnt *= factinv[b];
			cnt *= factinv[p];
			cnt *= factinv[q];
			cnt *= b == 0 ? (c == 0 ? 1 : 0) : nCr(c + b - 1, b - 1);
			ans += cnt;
		}
		printf("%d\n", ans.get());
	}
	return 0;
}

Submission Info

Submission Time
Task J - 123 Pairs
User anta
Language C++14 (GCC 5.4.1)
Score 1500
Code Size 2883 Byte
Status AC
Exec Time 45 ms
Memory 256 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 1500 / 1500
Status
AC × 2
AC × 52
Set Name Test Cases
Sample example0.txt, example1.txt
All 000.txt, 001.txt, 002.txt, 003.txt, 004.txt, 005.txt, 006.txt, 007.txt, 008.txt, 009.txt, 010.txt, 011.txt, 012.txt, 013.txt, 014.txt, 015.txt, 016.txt, 017.txt, 018.txt, 019.txt, 020.txt, 021.txt, 022.txt, 023.txt, 024.txt, 025.txt, 026.txt, 027.txt, 028.txt, 029.txt, 030.txt, 031.txt, 032.txt, 033.txt, 034.txt, 035.txt, 036.txt, 037.txt, 038.txt, 039.txt, 040.txt, 041.txt, 042.txt, 043.txt, 044.txt, 045.txt, 046.txt, 047.txt, 048.txt, 049.txt, example0.txt, example1.txt
Case Name Status Exec Time Memory
000.txt AC 37 ms 256 KB
001.txt AC 27 ms 256 KB
002.txt AC 27 ms 256 KB
003.txt AC 36 ms 256 KB
004.txt AC 27 ms 256 KB
005.txt AC 27 ms 256 KB
006.txt AC 35 ms 256 KB
007.txt AC 27 ms 256 KB
008.txt AC 27 ms 256 KB
009.txt AC 36 ms 256 KB
010.txt AC 35 ms 256 KB
011.txt AC 27 ms 256 KB
012.txt AC 27 ms 256 KB
013.txt AC 3 ms 256 KB
014.txt AC 3 ms 256 KB
015.txt AC 38 ms 256 KB
016.txt AC 6 ms 256 KB
017.txt AC 16 ms 256 KB
018.txt AC 6 ms 256 KB
019.txt AC 18 ms 256 KB
020.txt AC 19 ms 256 KB
021.txt AC 39 ms 256 KB
022.txt AC 25 ms 256 KB
023.txt AC 34 ms 256 KB
024.txt AC 40 ms 256 KB
025.txt AC 35 ms 256 KB
026.txt AC 37 ms 256 KB
027.txt AC 41 ms 256 KB
028.txt AC 35 ms 256 KB
029.txt AC 35 ms 256 KB
030.txt AC 38 ms 256 KB
031.txt AC 40 ms 256 KB
032.txt AC 32 ms 256 KB
033.txt AC 27 ms 256 KB
034.txt AC 19 ms 256 KB
035.txt AC 31 ms 256 KB
036.txt AC 16 ms 256 KB
037.txt AC 3 ms 256 KB
038.txt AC 45 ms 256 KB
039.txt AC 34 ms 256 KB
040.txt AC 31 ms 256 KB
041.txt AC 31 ms 256 KB
042.txt AC 30 ms 256 KB
043.txt AC 3 ms 256 KB
044.txt AC 3 ms 256 KB
045.txt AC 3 ms 256 KB
046.txt AC 3 ms 256 KB
047.txt AC 3 ms 256 KB
048.txt AC 3 ms 256 KB
049.txt AC 3 ms 256 KB
example0.txt AC 3 ms 256 KB
example1.txt AC 3 ms 256 KB