Submission #3285856


Source Code Expand

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;
 
#define fi first
#define se second
#define mp make_pair
#define pb push_back
 
typedef long long ll;
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef long double ld; 
typedef tree<ii, null_type, less<ii>, rb_tree_tag, tree_order_statistics_node_update> pbds;

vector<int> fact;
vector<int> ifact;
vector<int> inv;
vector<int> pow2;
const int MOD = (1e9 + 7);
int add(int a, int b)
{
	a+=b;
	while(a>=MOD) a-=MOD;
	return a;
}
int mult(int a, int b)
{
	return (a*1LL*b)%MOD;
}
int modpow(int a, int b)
{
	int r=1;
	while(b)
	{
		if(b&1) r=mult(r,a);
		a=mult(a,a);
		b>>=1;
	}
	return r;
}
int choose(int a, int b)
{
	if(a<b) return 0;
	if(b==0) return 1;
	if(a==b) return 1;
	return mult(fact[a],mult(ifact[b],ifact[a-b]));
}
int inverse(int a)
{
	return modpow(a,MOD-2);
}
void init(int _n)
{
	fact.clear(); ifact.clear(); inv.clear(); pow2.clear();
	fact.resize(_n+1);
	ifact.resize(_n+1);
	inv.resize(_n+1);
	pow2.resize(_n+1);
	pow2[0]=1;
	ifact[0]=1;
	fact[0]=1;
	for(int i=1;i<=_n;i++)
	{
		pow2[i]=add(pow2[i-1],pow2[i-1]);
		fact[i]=mult(fact[i-1],i);
		//ifact[i]=mult(ifact[i-1],inv[i]);
	}
	ifact[_n] = inverse(fact[_n]);
	for(int i=_n-1;i>=1;i--)
	{
		ifact[i] = mult(ifact[i + 1], i + 1);
	}
	for(int i=1;i<=_n;i++)
	{
		inv[i] = mult(fact[i-1],ifact[i]);
	}
}

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	init(5555);
	int n,a,b,c; cin>>n>>a>>b>>c; int res=0;
	for(int x=0;x<=n;x++)
	{
		for(int y=0;y<=n;y++)
		{
			int aleft = a - x;
			int bleft = b;
			int cleft = c - x - 3*y;
			if(aleft<0||bleft<0||cleft<0) continue;
			if(bleft%2!=0) continue;
			if(bleft==0&&cleft>0) continue;
			int ans = (bleft>0?choose(cleft+bleft/2 -1, cleft):1);
			ans = mult(ans, choose(bleft/2+aleft,aleft));
			ans = mult(ans, choose(bleft/2+aleft+x,x));
			ans = mult(ans, choose(bleft/2+aleft+x+y,y));
			res=add(res,ans);
		}
	}
	cout<<res<<'\n';
}

Submission Info

Submission Time
Task J - 123 Pairs
User zscoder
Language C++14 (GCC 5.4.1)
Score 1500
Code Size 2135 Byte
Status AC
Exec Time 54 ms
Memory 384 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 36 ms 384 KB
001.txt AC 19 ms 384 KB
002.txt AC 19 ms 384 KB
003.txt AC 19 ms 384 KB
004.txt AC 19 ms 384 KB
005.txt AC 18 ms 384 KB
006.txt AC 19 ms 384 KB
007.txt AC 19 ms 384 KB
008.txt AC 18 ms 384 KB
009.txt AC 19 ms 384 KB
010.txt AC 18 ms 384 KB
011.txt AC 18 ms 384 KB
012.txt AC 19 ms 384 KB
013.txt AC 2 ms 384 KB
014.txt AC 2 ms 384 KB
015.txt AC 44 ms 384 KB
016.txt AC 5 ms 384 KB
017.txt AC 15 ms 384 KB
018.txt AC 4 ms 384 KB
019.txt AC 18 ms 384 KB
020.txt AC 13 ms 384 KB
021.txt AC 42 ms 384 KB
022.txt AC 17 ms 384 KB
023.txt AC 24 ms 384 KB
024.txt AC 43 ms 384 KB
025.txt AC 23 ms 384 KB
026.txt AC 33 ms 384 KB
027.txt AC 41 ms 384 KB
028.txt AC 27 ms 384 KB
029.txt AC 30 ms 384 KB
030.txt AC 41 ms 384 KB
031.txt AC 43 ms 384 KB
032.txt AC 21 ms 384 KB
033.txt AC 18 ms 384 KB
034.txt AC 19 ms 384 KB
035.txt AC 27 ms 384 KB
036.txt AC 11 ms 384 KB
037.txt AC 1 ms 384 KB
038.txt AC 54 ms 384 KB
039.txt AC 18 ms 384 KB
040.txt AC 18 ms 384 KB
041.txt AC 25 ms 384 KB
042.txt AC 19 ms 384 KB
043.txt AC 1 ms 384 KB
044.txt AC 1 ms 384 KB
045.txt AC 1 ms 384 KB
046.txt AC 1 ms 384 KB
047.txt AC 1 ms 384 KB
048.txt AC 1 ms 384 KB
049.txt AC 1 ms 384 KB
example0.txt AC 1 ms 384 KB
example1.txt AC 2 ms 384 KB