Submission #20085

#	Time	Username	Problem	Language	Result	Execution time	Memory
20085		hongjun7	트리 (kriii4_X)	C++14	0 / 100	0 ms	1212 KiB

X

#include <stdio.h>
#include <map>
using namespace std;
const int mod = 1e9+7;
int N, M;
map<int, int> par, cnt;
int F(int x) {
	if (!par.count(x)) par[x] = x;
	if (par[x] == x) return x;
	return (par[x] = F(par[x]));
}
int mul(int x, int y) { return (long long)x * y % mod; }
int fm(int x, int y) {
	if (y <= 0) return 1;
	int r = fm(x, y / 2);
	r = mul(r, r);
	if (y % 2 == 1) r = mul(r, x);
	return r;
}
int main() {
	scanf("%d%d", &N, &M);
	bool ok = 1;
	for (int i = 1; i <= M; i++) {
		int x, y; scanf("%d%d", &x, &y);
		int px = F(x), py = F(y);
		if (px == py) ok = 0;
		else par[px] = py;
	}
	int res = 0;
	if (ok) {
		for (auto x : par) cnt[F(x.first)]++;
		res = fm(N, N - par.size() + cnt.size() - 2);
		for (auto x : cnt) res = mul(res, x.second);
	}
	printf("%d", res);
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 91