POJ2395 Out of Hay(最小生成树)

题意：

农场之间相互连接，要求输出最小连通中最长的那条边的权值

要点：

又是一道模板题，POJ上最小生成树咋这么多水题，要做点难的啊。

15347115

Seasonal

2395

Accepted

292K

79MS

C++

892B

2016-04-03 13:07:56

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<algorithm>
#define maxn 10005
using namespace std;
int p[maxn];
int m, n;
struct edge
{
	int u, v, len;
}e[maxn];

bool cmp(edge a, edge b)
{
	return a.len < b.len;
}
void init()
{
	for (int i = 1; i <= m; i++)
		p[i] = i;
}
int find(int x)
{
	if (p[x] == x) return x;
	return p[x] = find(p[x]);
}
bool merge(int x, int y)
{
	x = find(x);
	y = find(y);
	if (x != y)
	{
		p[x] = y;
		return true;
	}
	return false;
}
int kruskal()
{
	init();
	sort(e, e + n, cmp);
	int max = -1, edges = 0;
	for (int i = 0; i < n; i++)
	{
		if (merge(e[i].u, e[i].v))
		{
			if (max < e[i].len)
				max = e[i].len;
			edges++;
		}
		if (edges + 1 == m)
			return max;
	}
}

int main()
{
	while (~scanf("%d%d", &m, &n))
	{
		for (int i = 0; i < n; i++)
			scanf("%d%d%d", &e[i].u, &e[i].v, &e[i].len);
		printf("%d\n", kruskal());
	}
	return 0;
}