Submission #19250

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
19250	2016-02-23T02:11:47 Z	kaTkaHr	악수 (kriii4_D)	C++14	5 / 100	3000 ms	25256 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);
	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

#	Verdict	Execution time	Memory	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

#	Verdict	Execution time	Memory	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	2 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	49 ms	2684 KB	Output is correct
14	Correct	81 ms	3080 KB	Output is correct
15	Correct	129 ms	3740 KB	Output is correct
16	Correct	209 ms	4532 KB	Output is correct
17	Correct	314 ms	5588 KB	Output is correct
18	Correct	484 ms	7040 KB	Output is correct
19	Correct	717 ms	9020 KB	Output is correct
20	Correct	1073 ms	11660 KB	Output is correct
21	Correct	1569 ms	14960 KB	Output is correct
22	Correct	2265 ms	19448 KB	Output is correct
23	Execution timed out	3000 ms	25256 KB	Program timed out
24	Halted	0 ms	0 KB	-