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답안 #19887

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
19887 2016-02-25T06:45:22 Z gs13068 트리 (kriii4_X) C++
100 / 100
 640 ms 16260 KB 
#include <cstdio>
#include <map>

const int p = 1000000007;

using namespace std;

int pw(int x, int y)
{
	return y & 1 ? (long long)pw(x, y ^ 1)*x%p : y ? pw((long long)x*x%p, y >> 1) : 1;
}

map<int, int> M, S;

int f(int x)
{
	if (M.find(x) == M.end()) M[x] = x;
	int t = M[x];
	return x == t ? x : M[x] = f(t);
}

void g(int x, int y)
{
	x = f(x);
	y = f(y);
	if (S.find(x) == S.end()) S[x] = 1;
	if (S.find(y) == S.end()) S[y] = 1;
	S[x] += S[y];
	M[y] = M[x];
}

int main()
{
	map<int, int>::iterator it;
	int i, j, k, n, m, r;
	scanf("%d%d", &n, &m);
	for (k = 0; k < m;k++)
	{
		scanf("%d%d", &i, &j);
		if (f(i) == f(j))
		{
			puts("0");
			return 0;
		}
		g(i, j);
	}
	if (m == n - 1)
	{
		puts("1");
		return 0;
	}
	r = pw(n, n - m - 2);
	for (it = S.begin(); it != S.end(); it++) if (it->first == f(it->first)) r = (long long)r * it->second % p;
	printf("%d", r);
}

Subtask #1
9.0 / 9.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 1212 KB Output is correct
2 Correct 0 ms 1212 KB Output is correct
3 Correct 0 ms 1212 KB Output is correct
4 Correct 0 ms 1212 KB Output is correct
5 Correct 0 ms 1212 KB Output is correct
6 Correct 0 ms 1212 KB Output is correct
7 Correct 0 ms 1212 KB Output is correct
8 Correct 0 ms 1212 KB Output is correct
9 Correct 0 ms 1212 KB Output is correct
10 Correct 0 ms 1212 KB Output is correct
11 Correct 0 ms 1212 KB Output is correct
12 Correct 0 ms 1212 KB Output is correct
13 Correct 0 ms 1212 KB Output is correct
14 Correct 0 ms 1212 KB Output is correct
15 Correct 0 ms 1212 KB Output is correct
16 Correct 0 ms 1212 KB Output is correct
17 Correct 0 ms 1212 KB Output is correct
18 Correct 0 ms 1212 KB Output is correct
19 Correct 0 ms 1212 KB Output is correct
20 Correct 0 ms 1212 KB Output is correct
21 Correct 0 ms 1212 KB Output is correct
22 Correct 0 ms 1212 KB Output is correct
23 Correct 0 ms 1212 KB Output is correct
24 Correct 0 ms 1212 KB Output is correct
25 Correct 0 ms 1212 KB Output is correct
26 Correct 0 ms 1212 KB Output is correct
27 Correct 0 ms 1212 KB Output is correct
28 Correct 0 ms 1212 KB Output is correct
29 Correct 0 ms 1212 KB Output is correct
30 Correct 0 ms 1212 KB Output is correct

Subtask #2
91.0 / 91.0

# 결과 실행 시간 메모리 Grader output
1 Correct 43 ms 2400 KB Output is correct
2 Correct 126 ms 3588 KB Output is correct
3 Correct 129 ms 3852 KB Output is correct
4 Correct 43 ms 2268 KB Output is correct
5 Correct 86 ms 3192 KB Output is correct
6 Correct 587 ms 15600 KB Output is correct
7 Correct 593 ms 15864 KB Output is correct
8 Correct 103 ms 4776 KB Output is correct
9 Correct 576 ms 16260 KB Output is correct
10 Correct 591 ms 14544 KB Output is correct
11 Correct 577 ms 10056 KB Output is correct
12 Correct 558 ms 9924 KB Output is correct
13 Correct 570 ms 10056 KB Output is correct
14 Correct 565 ms 10056 KB Output is correct
15 Correct 571 ms 10188 KB Output is correct
16 Correct 466 ms 10320 KB Output is correct
17 Correct 460 ms 10320 KB Output is correct
18 Correct 0 ms 1212 KB Output is correct
19 Correct 626 ms 10452 KB Output is correct
20 Correct 616 ms 10452 KB Output is correct
21 Correct 566 ms 9924 KB Output is correct
22 Correct 577 ms 10188 KB Output is correct
23 Correct 603 ms 10584 KB Output is correct
24 Correct 612 ms 10452 KB Output is correct
25 Correct 383 ms 10584 KB Output is correct
26 Correct 372 ms 10584 KB Output is correct
27 Correct 584 ms 14280 KB Output is correct
28 Correct 566 ms 14280 KB Output is correct
29 Correct 614 ms 10584 KB Output is correct
30 Correct 640 ms 10584 KB Output is correct