SPOJ PT07Y

最新推荐文章于 2019-10-31 20:43:01 发布

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最新推荐文章于 2019-10-31 20:43:01 发布

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分类专栏： SPOJ 文章标签： C++ SPOJ

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// http://www.spoj.com/problems/PT07Y/
#include <iostream>
using namespace std;
int findroot(int* points, int p) {
	while (points[p] != p) p = points[p];
	return p;
}
int main() {
	int V, E;
	cin >> V >> E;
	int *points = new int[V+1];
	for (int i = 1; i <= V; i++) {
		points[i] = i;
	}
	bool YES = true;
	for (int i = 0; i < E; i++) {
		int u, v;
		cin >> u >> v;
		if (!YES) continue;
		int rootu = findroot(points, u);
		int rootv = findroot(points, v);
		if (rootu != rootv) {
			points[v] = u;
			continue;
		}
		else {
			YES = false;
		}
	}
	if (YES) {
		cout << "YES" << endl;
	}
	else {
		cout << "NO" << endl;
	}
	return 0;
}