oj.uz

답안 #19749

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
19749 2016-02-25T05:16:15 Z xhae 트리 (kriii4_X) C++14
9 / 100
 1000 ms 15672 KB 
#include <cstdio>
#include <map>
#include <unordered_map>
#include <vector>
#include <algorithm>

using namespace std;

const int mod = 1000000007;
unordered_map<int, int> groups;
unordered_map<int, int> groupsize;

int get_root(int a) {
	int t = a;
	while (a != groups[a])
		a = groups[a];
	while (t != groups[t])
	{
		int p = groups[t];
		groups[t] = a;
		t = p;
	}
	return a;
}

bool group_merge(int a, int b) {
	if (!groups.count(a)) {
		groups[a] = a;
		groupsize[a] = 1;
	}
	if (!groups.count(b)) {
		groups[b] = b;
		groupsize[b] = 1;
	}
	a = get_root(a);
	b = get_root(b);
	if (a == b)
		return false;
	if (groupsize[a] < groupsize[b]) {
		swap(a, b);
	}
	groups[b] = a;
	groupsize[a] += groupsize[b];
	return true;
}

int main() {
	int n, m;
	scanf("%d%d", &n, &m);
	long long ans = 1;
	for (int i = 0; i < m; i++) {
		int a, b;
		scanf("%d%d", &a, &b);
		a--, b--;
		if (!group_merge(a, b)) {
			ans = 0;
		}
	}
	if (m >= n)
		ans = 0;
	int c = n - m;
	if (c >= 2) {
		for (int i = 0; i < c - 2; i++) {
			ans *= n;
			ans %= mod;
		}
		for (auto kv : groups) {
			if (kv.first == kv.second) {
				ans *= groupsize[kv.first];
				ans %= mod;
			}
		}
	}
	printf("%lld\n", ans);
	return 0;
}

Subtask #1
9.0 / 9.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 1584 KB Output is correct
2 Correct 0 ms 1584 KB Output is correct
3 Correct 0 ms 1584 KB Output is correct
4 Correct 0 ms 1584 KB Output is correct
5 Correct 0 ms 1584 KB Output is correct
6 Correct 0 ms 1584 KB Output is correct
7 Correct 0 ms 1584 KB Output is correct
8 Correct 0 ms 1584 KB Output is correct
9 Correct 0 ms 1584 KB Output is correct
10 Correct 0 ms 1584 KB Output is correct
11 Correct 0 ms 1584 KB Output is correct
12 Correct 0 ms 1584 KB Output is correct
13 Correct 0 ms 1584 KB Output is correct
14 Correct 0 ms 1584 KB Output is correct
15 Correct 0 ms 1584 KB Output is correct
16 Correct 0 ms 1584 KB Output is correct
17 Correct 0 ms 1584 KB Output is correct
18 Correct 0 ms 1584 KB Output is correct
19 Correct 0 ms 1584 KB Output is correct
20 Correct 0 ms 1584 KB Output is correct
21 Correct 0 ms 1584 KB Output is correct
22 Correct 0 ms 1584 KB Output is correct
23 Correct 0 ms 1584 KB Output is correct
24 Correct 0 ms 1584 KB Output is correct
25 Correct 0 ms 1584 KB Output is correct
26 Correct 0 ms 1584 KB Output is correct
27 Correct 0 ms 1584 KB Output is correct
28 Correct 0 ms 1584 KB Output is correct
29 Correct 0 ms 1584 KB Output is correct
30 Correct 0 ms 1584 KB Output is correct

Subtask #2
0.0 / 91.0

# 결과 실행 시간 메모리 Grader output
1 Correct 10 ms 2556 KB Output is correct
2 Correct 24 ms 3704 KB Output is correct
3 Correct 23 ms 3836 KB Output is correct
4 Correct 11 ms 2556 KB Output is correct
5 Correct 21 ms 3440 KB Output is correct
6 Correct 163 ms 15144 KB Output is correct
7 Correct 160 ms 15408 KB Output is correct
8 Correct 95 ms 7920 KB Output is correct
9 Correct 163 ms 15672 KB Output is correct
10 Correct 147 ms 14484 KB Output is correct
11 Correct 571 ms 9416 KB Output is correct
12 Correct 627 ms 9416 KB Output is correct
13 Correct 901 ms 9416 KB Output is correct
14 Correct 605 ms 9416 KB Output is correct
15 Correct 639 ms 9548 KB Output is correct
16 Correct 749 ms 9548 KB Output is correct
17 Correct 804 ms 9548 KB Output is correct
18 Execution timed out 1000 ms 1580 KB Program timed out
19 Halted 0 ms 0 KB -