답안 #19926

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
19926 2016-02-25T07:20:02 Z tonyjjw 악수 (kriii4_D) C++14
100 / 100
669 ms 66740 KB
//*
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <stdlib.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <numeric>
#include <functional>
#define MOD 1000000007
#define MAX 0x3f3f3f3f
#define MAX2 0x3f3f3f3f3f3f3f3fll
#define ERR 1e-10
#define mp make_pair
#define all(x) (x).begin(), (x).end()
#pragma warning(disable:4996)
using namespace std;

typedef long long ll;
typedef long double ldb;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;

ll mul_inv(ll a, ll b=MOD)
{
	ll b0=b, t, q;
	ll x0=0, x1=1;
	if(b == 1) return 1;
	while(a > 1)
	{
		q=a/b;
		t=b, b=a%b, a=t;
		t=x0, x0=x1-q*x0, x1=t;
	}
	if(x1 < 0) x1+=b0;
	return x1;
}

ll ncr[2600][2600];
ll d[200][2600];
ll e[200][2600];
ll f[200][2600];
ll fac[2600];

int n;

ll npr(ll n, ll r)
{
	if(r > n) return 0;
	return fac[n]*mul_inv(fac[n-r])%MOD;
}

void addmod(ll &x, ll y)
{
	x+=y, x%=MOD;
}

int main()
{
	int i, j, k;
	cin>>n;
	if(n == 1) return !printf("0");
	for(i=0;i<2600;i++) for(j=0;j<=i;j++) ncr[i][j]=j==0||j==i?1:ncr[i-1][j-1]+ncr[i-1][j], ncr[i][j]%=MOD;
	fac[0]=1;
	for(i=1;i<2600;i++) fac[i]=fac[i-1]*i, fac[i]%=MOD;
	d[1][0]=1;
	e[1][0]=0;
	f[1][0]=1;
	d[2][0]=0;
	e[2][0]=1;
	f[2][0]=1;
	d[2][1]=1;
	e[2][1]=0;
	f[2][1]=1;
	for(i=3;i<=n;i++)
	{
		for(j=0;j<=ncr[i][2];j++)
		{
			f[i][j]=npr(ncr[i][2], j);
			ll xsum=0;
			for(int s=1;s<=i-1;s++)
			{
				ll sum=0;
				for(k=0;k<=j;k++)
				{
					addmod(sum, d[s][k]*f[i-s][j-k]%MOD*ncr[j][k]);
				}
				sum*=ncr[i-1][s-1], sum%=MOD;
				xsum+=sum, xsum%=MOD;
			}
			e[i][j]=xsum;
			d[i][j]=(f[i][j]-xsum)%MOD;
			if(d[i][j] < 0) d[i][j]+=MOD;
		}
	}
	ll ex=0;
	ll tot=fac[ncr[n][2]];
	for(j=1;j<=ncr[n][2];j++)
	{
		ex+=j*(d[n][j]*fac[ncr[n][2]-j]%MOD-d[n][j-1]*fac[ncr[n][2]-(j-1)]%MOD+MOD)%MOD;
		ex%=MOD;
	}
	ex*=mul_inv(tot);
	ex%=MOD;
	cout<<ex;
	return 0;
}
//*/
# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 66740 KB Output is correct
2 Correct 11 ms 66740 KB Output is correct
3 Correct 4 ms 66740 KB Output is correct
4 Correct 12 ms 66740 KB Output is correct
5 Correct 8 ms 66740 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 66740 KB Output is correct
2 Correct 3 ms 66740 KB Output is correct
3 Correct 10 ms 66740 KB Output is correct
4 Correct 12 ms 66740 KB Output is correct
5 Correct 0 ms 66740 KB Output is correct
6 Correct 8 ms 66740 KB Output is correct
7 Correct 20 ms 66740 KB Output is correct
8 Correct 17 ms 66740 KB Output is correct
9 Correct 13 ms 66740 KB Output is correct
10 Correct 13 ms 66740 KB Output is correct
11 Correct 19 ms 66740 KB Output is correct
12 Correct 16 ms 66740 KB Output is correct
13 Correct 25 ms 66740 KB Output is correct
14 Correct 28 ms 66740 KB Output is correct
15 Correct 26 ms 66740 KB Output is correct
16 Correct 30 ms 66740 KB Output is correct
17 Correct 30 ms 66740 KB Output is correct
18 Correct 29 ms 66740 KB Output is correct
19 Correct 51 ms 66740 KB Output is correct
20 Correct 51 ms 66740 KB Output is correct
21 Correct 70 ms 66740 KB Output is correct
22 Correct 71 ms 66740 KB Output is correct
23 Correct 97 ms 66740 KB Output is correct
24 Correct 107 ms 66740 KB Output is correct
25 Correct 133 ms 66740 KB Output is correct
26 Correct 139 ms 66740 KB Output is correct
27 Correct 188 ms 66740 KB Output is correct
28 Correct 203 ms 66740 KB Output is correct
29 Correct 255 ms 66740 KB Output is correct
30 Correct 302 ms 66740 KB Output is correct
31 Correct 356 ms 66740 KB Output is correct
32 Correct 421 ms 66740 KB Output is correct
33 Correct 492 ms 66740 KB Output is correct
34 Correct 569 ms 66740 KB Output is correct
35 Correct 669 ms 66740 KB Output is correct