답안 #19487

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
19487	2016-02-24T14:06:52 Z	kaTkaHr	악수 (kriii4_D)	C++14	5 / 100	3000 ms	34544 KB

D

#include <stdio.h>
#include<vector>
#include <algorithm>
#include <map>

using namespace std;

typedef long long ll;

const int MX = 45, MM = 1000000007;

template<typename T>
T pw(T A, ll B){
  T R = 1;
  while(B){
    if( B&1 ) R = R * A;
    A = A * A; B /= 2;
  }
  return R;
}

ll rv(ll A){ 
  ll R = 1, B = MM-2;
  while(B){
    if( B&1 ) R = R * A % MM;
    A = A * A % MM; B /= 2;
  }
  return R;
}
/*
struct frac{
  ll A, B;
		frac(ll A):A(A), B(1){}
  frac(ll a, ll b){
    A = (a%MM+MM) % MM;
    B = (b%MM+MM) % MM;
  }
  frac(){A = 0, B = 1;}
  frac operator+ (const frac &l)const{
    return frac((A * l.B + B * l.A) % MM, B * l.B % MM);
  }
  frac operator*(const frac &l)const{
    return frac(A*l.A % MM, B*l.B % MM);
  }
  frac operator/(const frac &l)const{
    return frac(A*l.B % MM, B*l.A % MM);
  }
  frac operator- (const frac &l)const{
    return frac((A*l.B - B*l.A%MM + MM) % MM, B*l.B % MM);
  }
  ll v(){ return A * rv(B) % MM; }
};// */
//*
struct frac{
  ll A;
		frac(ll A):A((A%MM+MM)%MM){}
  frac(ll a, ll b){
			a = (a%MM+MM)%MM;
			b = (b%MM+MM)%MM;
			A = rv(b) * a % MM;
  }
  frac(){A = 0;}
  frac operator+ (const frac &l)const{
			return l.A + A >= MM? l.A + A - MM: l.A + A;
  }
  frac operator*(const frac &l)const{
			return l.A * A % MM;
  }
  frac operator/(const frac &l)const{
			return A * rv(l.A) % MM;
  }
  frac operator- (const frac &l)const{
			return A >= l.A? A-l.A: A-l.A + MM;
  }
  ll v(){ return A; }
};// */

frac D[MX][MX*MX], E[MX][MX*MX], C[MX*MX][MX*MX];

int main()
{
	int N, T;
	scanf("%d", &N); T = N*(N-1) / 2;

	C[0][0] = 1;
	for(int i = 1; i <= T || i <= N; i++){
		C[i][0] = 1;
		for(int j = 1; j <= i; j++){
			C[i][j] = C[i-1][j-1] + C[i-1][j];
		}
	}

	D[1][0] = E[1][0] = 1;
	for(int i = 2; i <= N; i++){
		for(int x = i-1; x <= i*(i-1)/2; x++){
			for(int k = 1; k <= i-1; k++){
				for(int l = 0; l <= x-1; l++){
					E[i][x] = E[i][x] + D[k][l] * D[i-k][x-l-1] * frac(k*(i-k), 1) * C[i][k] * C[x-1][l];
				}
			}
			E[i][x] = E[i][x] / 2;
			D[i][x] = D[i][x-1] * frac(i*(i-1)/2 - x + 1, 1) + E[i][x];
		}
	}
	frac ans = 0, mul = 1;
	frac tot = 0;
	for(int i = 0; i <= T; i++){
		tot = tot + E[N][i] * mul;
		ans = ans + E[N][i] * i * mul;
		mul = mul * frac(1, T-i);
	}
	printf("%lld\n", ans.v());
}

Subtask #1

5.0 / 5.0

#	결과	실행 시간	메모리	Grader output
1	Correct	4 ms	34544 KB	Output is correct
2	Correct	0 ms	34544 KB	Output is correct
3	Correct	4 ms	34544 KB	Output is correct
4	Correct	0 ms	34544 KB	Output is correct
5	Correct	0 ms	34544 KB	Output is correct

Subtask #2

0.0 / 95.0

#	결과	실행 시간	메모리	Grader output
1	Correct	4 ms	34544 KB	Output is correct
2	Correct	4 ms	34544 KB	Output is correct
3	Correct	4 ms	34544 KB	Output is correct
4	Correct	0 ms	34544 KB	Output is correct
5	Correct	3 ms	34544 KB	Output is correct
6	Correct	10 ms	34544 KB	Output is correct
7	Correct	4 ms	34544 KB	Output is correct
8	Correct	11 ms	34544 KB	Output is correct
9	Correct	9 ms	34544 KB	Output is correct
10	Correct	16 ms	34544 KB	Output is correct
11	Correct	24 ms	34544 KB	Output is correct
12	Correct	43 ms	34544 KB	Output is correct
13	Correct	53 ms	34544 KB	Output is correct
14	Correct	76 ms	34544 KB	Output is correct
15	Correct	93 ms	34544 KB	Output is correct
16	Correct	124 ms	34544 KB	Output is correct
17	Correct	165 ms	34544 KB	Output is correct
18	Correct	219 ms	34544 KB	Output is correct
19	Correct	282 ms	34544 KB	Output is correct
20	Correct	356 ms	34544 KB	Output is correct
21	Correct	458 ms	34544 KB	Output is correct
22	Correct	569 ms	34544 KB	Output is correct
23	Correct	704 ms	34544 KB	Output is correct
24	Correct	870 ms	34544 KB	Output is correct
25	Correct	1072 ms	34544 KB	Output is correct
26	Correct	1300 ms	34544 KB	Output is correct
27	Correct	1575 ms	34544 KB	Output is correct
28	Correct	1902 ms	34544 KB	Output is correct
29	Correct	2267 ms	34544 KB	Output is correct
30	Correct	2701 ms	34544 KB	Output is correct
31	Execution timed out	3000 ms	34544 KB	Program timed out
32	Halted	0 ms	0 KB	-