PHP实现克鲁斯卡尔算法实例解析,克鲁斯卡尔算法实例_PHP教程
PHP实现克鲁斯卡尔算法实例解析,克鲁斯卡尔算法实例
本文实例展示了PHP实现的格鲁斯卡尔算法(kruscal)的实现方法,分享给大家供大家参考。相信对于大家的PHP程序设计有一定的借鉴价值。
具体代码如下:
'10', 'af' => '11', 'gb' => '16', 'fg' => '17', 'bc' => '18', 'bi' => '12', 'ci' => '8', 'cd' => '22', 'di' => '21', 'dg' => '24', 'gh' => '19', 'dh' => '16', 'de' => '20', 'eh' => '7', 'fe' => '26' ); $test = new Edge($a, $b); print_r($test->kruscal()); ?>
edge.php文件代码如下:
begin = $begin; $this->end = $end; $this->weight = $weight; } public function getBegin() { return $this->begin; } public function getEnd() { return $this->end; } public function getWeight() { return $this->weight; } } class Edge { //边集数组实现图 private $vexs; //顶点集合 private $arc; //边集合 private $arcData; //要构建图的边信息 private $krus; //kruscal算法时存放森林信息 public function Edge($vexsData, $arcData) { $this->vexs = $vexsData; $this->arcData = $arcData; $this->createArc(); } //创建边 private function createArc() { foreach ($this->arcData as $key => $value) { $key = str_split($key); $this->arc[] = new EdgeArc($key[0], $key[1], $value); } } //对边数组按权值排序 public function sortArc() { $this->quicklySort(0, count($this->arc) - 1, $this->arc); return $this->arc; } //采用快排 private function quicklySort($begin, $end, &$item) { if ($begin = $end)) return; $key = $this->excuteSort($begin, $end, $item); $this->quicklySort(0, $key - 1, $item); $this->quicklySort($key + 1, $end, $item); } private function excuteSort($begin, $end, &$item) { $key = $item[$begin]; $left = array(); $right = array(); for ($i = ($begin + 1); $i getWeight() getWeight()) { $left[] = $item[$i]; } else { $right[] = $item[$i]; } } $return = $this->unio($left, $right, $key); $k = 0; for ($i = $begin; $i krus = array(); $this->sortArc(); foreach ($this->vexs as $value) { $this->krus[$value] = "0"; } foreach ($this->arc as $key => $value) { $begin = $this->findRoot($value->getBegin()); $end = $this->findRoot($value->getEnd()); if ($begin != $end) { $this->krus[$begin] = $end; echo $value->getBegin() . "-" . $value->getEnd() . ":" . $value->getWeight() . "\n"; } } } //查找子树的尾结点 private function findRoot($node) { while ($this->krus[$node] != "0") { $node = $this->krus[$node]; } return $node; } } ?>
感兴趣的读者可以调试运行一下本文克鲁斯卡尔算法实例,相信会有新的收获。
你确定要用邻接表吗?因为在克鲁斯卡尔算法里只需要存储边及费用,用邻接表意义不大,还不好排序。 最好结合具体题目实现,我这里有个题目,里面有完整的代码,慢慢理解就是了 blog.csdn.net/...751786
以下给出并查集实现的克鲁斯卡尔算法,求解生成网络的最小费用,并输出生成网络里的路径。
#include
#include
using namespace std;
int p[1001],rank[1001];
int cho[1001];
struct edge
{
int u,v,w;//u表示起始点编号,v表示终点编号,w表示该路径费用
}e[15001];
int n,m;//n表示点的个数,m表示路径数
void Init()
{
int i;
for(i=1;i {
p[i]=i;
rank[i]=0;
}
}
bool cmp(edge a,edge b)
{
return a.w
int Find(int t)
{
if(p[t]!=t)
{
p[t]=Find(p[t]);
}
return p[t];
}
int Union(int a,int b)
{
int x,y;
x=Find(a);
y=Find(b);
if(rank[x]>rank[y])
{
p[y]=x;
}
else
{
p[x]=y;
if(rank[x]==rank[y])
rank[y]++;
}
return 0;
}
int main()
{
scanf("%d%d",&n,&m);
int i,j;
for(i=0;i
scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);
}
Init();
sort(e,e+m,cmp);
int cnt=0,ans=0;
for(i=0;i
if(Find(e[i].u)!=Find(e[i].v))
{
cnt++;
ans+=e[i].w;
Union(e[i].u,e[i].v);
cho[++cho[0]]=i;
if(cnt==n-1)
break;
}
}
printf("%d\n",ans);
for(j=1;j {
printf("%d %d\n",e[cho[j]].u,e[cho[j]].v);
}
return 0;
}...余下全文>>
里面还有很多,感兴趣也可以看看