PHP实现克鲁斯卡尔算法实例解析
发布:smiling 来源: PHP粉丝网 添加日期:2021-04-08 20:48:29 浏览: 评论:0
这篇文章主要介绍了PHP实现克鲁斯卡尔算法实例解析,是PHP程序设计中一个比较经典的应用,需要的朋友可以参考下
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:
- <?php
- require 'edge.php';
- $a = array(
- 'a',
- 'b',
- 'c',
- 'd',
- 'e',
- 'f',
- 'g',
- 'h',
- 'i'
- );
- $b = array(
- 'ab' => '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:
- <?php
- //边集数组的边类
- class EdgeArc {
- private $begin; //起始点
- private $end; //结束点
- private $weight; //权值
- public function EdgeArc($begin, $end, $weight) {
- $this->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 ($begin < 0($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 <= $end; $i++) {
- if ($item[$i]->getWeight() <= $key->getWeight()) {
- $left[] = $item[$i];
- } else {
- $right[] = $item[$i];
- }
- }
- $return = $this->unio($left, $right, $key);
- $k = 0;
- for ($i = $begin; $i <= $end; $i++) {
- $item[$i] = $return[$k];
- $k++;
- }
- return $begin + count($left);
- }
- private function unio($left, $right, $key) {
- return array_merge($left, array(
- $key
- ) , $right);
- }
- //kruscal算法
- public function kruscal() {
- $this->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。
Tags: PHP鲁斯卡尔算法
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