poj2395

krustra最小生成树

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#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
using namespace std;

#define maxm 10005
#define maxn 2005

struct Edge
{
int a, b, l;
}edge[maxm];

int father[maxn];
int n, m;

bool operator < (const Edge &a, const Edge &b)
{
return a.l < b.l;
}

int getanc(int a)
{
if (a == father[a])
return a;
return father[a] = getanc(father[a]);
}

bool connected(int a, int b)
{
if (getanc(a) == getanc(b))
return true;
return false;
}

void merge(int a, int b)
{
father[getanc(a)] = getanc(b);
}

int main()
{
//freopen("t.txt", "r", stdin);
scanf("%d%d", &n, &m);
for (int i = 0; i < n; i++)
father[i] = i;
for (int i = 0; i < m; i++)
{
scanf("%d%d%d", &edge[i].a, &edge[i].b, &edge[i].l);
edge[i].a--;
edge[i].b--;
}
sort(edge, edge + m);
int tot = 0;
int ans = 0;
int i = 0;
while (tot < n - 1)
{
while (i < m && connected(edge[i].a, edge[i].b))
i++;
if (i >= m)
break;
merge(edge[i].a, edge[i].b);
if (ans < edge[i].l)
ans = edge[i].l;
tot++;
}
printf("%d\n", ans);
return 0;
}

转载于:https://www.cnblogs.com/rainydays/archive/2011/05/27/2059606.html