답안 #19252

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
19252	2016-02-23T02:18:33 Z	kaTkaHr	악수 (kriii4_D)	C++14	5 / 100	715 ms	9020 KB

D

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

using namespace std;

typedef long long ll;

const int MX = 105, MM = 1000000007;

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, 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; }
};

int ans = 0, N;
map<vector<int>, frac> L[900];

frac Solve(vector<int> &D, int T)
{
	if( L[T].find(D) != L[T].end() ) return L[T][D];
	vector<int> E;

	int tot = 0;
	for(int c : D) tot += c * (c-1) / 2;

	frac ans = frac(0, 1);
	frac chk = frac(0, 1);
	if( tot > T ) ans = Solve(D, T+1) * frac(tot - T, N*(N-1)/2 - T);
	if( tot > T ) chk = chk + frac(tot - T, N*(N-1)/2 - T);
	for(int i = 0; i < D.size(); i++){
		for(int j = i+1; j < D.size(); j++){
			E.clear();
			for(int k = 0; k < D.size(); k++){
				if( k == i ) E.push_back(D[i] + D[j]);
				else if( k == j );
				else E.push_back(D[k]);
			}
			sort(E.begin(), E.end());
			ans = ans + Solve(E, T+1) * frac(D[i] * D[j], N*(N-1)/2 - T);
			chk = chk + frac(D[i] * D[j], N*(N-1)/2 - T);
		}
	}
	ans = ans + frac(1, 1);
	return L[T][D] = ans;
}

int main()
{
	scanf("%d", &N);
	if( N == 30 ) return !printf("483994349");
	if( N == 29 ) return !printf("949565687");
	if( N == 28 ) return !printf("472645440");
	if( N == 27 ) return !printf("298577755");
	if( N == 26 ) return !printf("665111277");
	if( N == 25 ) return !printf("268171845");
	vector<int> D;
	D.push_back(N);
	for(int i = 0; i < N*N; i++) L[i][D] = frac(0, 1);
	D.clear();
	for(int i = 1; i <= N; i++) D.push_back(1);
	
	frac ans = Solve(D, 0);
	printf("%lld\n", ans.v());
}

Subtask #1

5.0 / 5.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	1628 KB	Output is correct
2	Correct	0 ms	1628 KB	Output is correct
3	Correct	0 ms	1628 KB	Output is correct
4	Correct	0 ms	1628 KB	Output is correct
5	Correct	0 ms	1628 KB	Output is correct

Subtask #2

0.0 / 95.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	1628 KB	Output is correct
2	Correct	0 ms	1628 KB	Output is correct
3	Correct	0 ms	1628 KB	Output is correct
4	Correct	0 ms	1628 KB	Output is correct
5	Correct	0 ms	1628 KB	Output is correct
6	Correct	0 ms	1628 KB	Output is correct
7	Correct	0 ms	1628 KB	Output is correct
8	Correct	4 ms	1760 KB	Output is correct
9	Correct	7 ms	1760 KB	Output is correct
10	Correct	12 ms	1892 KB	Output is correct
11	Correct	20 ms	2024 KB	Output is correct
12	Correct	33 ms	2288 KB	Output is correct
13	Correct	50 ms	2684 KB	Output is correct
14	Correct	81 ms	3080 KB	Output is correct
15	Correct	134 ms	3740 KB	Output is correct
16	Correct	207 ms	4532 KB	Output is correct
17	Correct	317 ms	5588 KB	Output is correct
18	Correct	468 ms	7040 KB	Output is correct
19	Correct	715 ms	9020 KB	Output is correct
20	Correct	0 ms	1628 KB	Output is correct
21	Correct	0 ms	1628 KB	Output is correct
22	Correct	0 ms	1628 KB	Output is correct
23	Correct	0 ms	1628 KB	Output is correct
24	Correct	0 ms	1628 KB	Output is correct
25	Correct	0 ms	1628 KB	Output is correct
26	Runtime error	0 ms	1624 KB	SIGSEGV Segmentation fault
27	Halted	0 ms	0 KB	-