最近在准备各种面试，复习了一波算法基础，关于什么是堆排序我就不多说了，这里说的很详细，不明白的可以参考一下：
https://jingyan.baidu.com/article/5225f26b057d5de6fa0908f3.html
废话不多说，贴完整代码：
<?php /** * Created by PhpStorm. * User: KeenSting * Date: 2017/12/7 * Time: 下午5:47 * Name: 梁小苍 * Phone: 13126734215 * QQ: 707719848 * File Description: 堆排序 */ //节点类 class Node{ public $value; //节点值 public $left; //左子节点 public $right; //右子节点 public $father; //父节点 public $pos_in_father; //在父节点的位置,左还是右 public function __construct($num) { $this->value = $num; $this->left = $this->right = $this->father = null; $this->pos_in_father = null;//1 左,2右 } } //测试堆排序类 class ATest{ private $list; //存放节点列表,节点间的关系用引用表示 private $num; //节点数 private $result; //结果集 public function __construct(array $data) { $this->list = $this->result = []; $this->num = count($data); $this->createHeap($data,$this->num); $this->initHeap(); } //执行排序 public function run() { //交换堆顶和堆尾的节点值,移除尾部节点,加入到输出中 while(true) { $size = count($this->list); if($size>2) { array_push($this->result,$this->list[0]->value);//堆顶的数加入结果集 $tail = array_pop($this->list); $this->list[0]->value = $tail->value;//堆尾的数放到堆顶,在此调整 if($father = &$tail->father)//释放尾部节点,修改父节点中子节点信息,置null { if($tail->pos_in_father==1) $father->left = null; else $father->right = null; } unset($tail); $this->nodeAdjust($this->list[0]); }else//只有两个元素的时候就释放掉 { array_push($this->result,$this->list[0]->value); array_push($this->result,$this->list[1]->value); unset($this->list); break; } } //打印降序结果 print_r($this->result); //打印升序结果 print_r(array_reverse($this->result)); } //创建堆结构,结果存放在list中,按从上到下,从左到右排列 private function createHeap($data,$length) { //使用array_shift作为队列输出 $root = new Node($data[0]); $queue = []; $index = 0; array_push($queue,$root); while($queue) { $father = array_shift($queue); $index++; if($index<$length)//创建左节点 { $node1 = new Node($data[$index]); $father->left = $node1; $node1->father = $father; $node1->pos_in_father = 1; array_push($queue,$node1); $index++; } if($index<$length)//创建右节点 { $node2 = new Node($data[$index]); $father->right = $node2; $node2->father = $father; $node2->pos_in_father = 2; array_push($queue,$node2); } array_push($this->list,$father); } } //初始化为大顶堆 private function initHeap() { for($i=$this->num-1;$i>=0;$i--) { $tmp = &$this->list[$i]; $this->nodeAdjust($tmp); } } //递归调整节点以及其子节点,保证大顶堆的特性 private function nodeAdjust(&$tmp) { if(($left = &$tmp->left)!=null)//左子树 { if(($right = &$tmp->right)!=null)//右子树在 { if($right->value > $left->value)//先比较子节点大小 { if($tmp->value < $right->value)//父节点和右节点交换 { $tmp_val = $right->value; $right->value = $tmp->value; $tmp->value = $tmp_val; $this->nodeAdjust($right); } }else { if($tmp->value < $left->value)//父节点和左节点交换 { $tmp_val = $left->value; $left->value = $tmp->value; $tmp->value = $tmp_val; $this->nodeAdjust($left); } } }else{//没有右子树 if($tmp->value < $left->value) { $tmp_val = $left->value; $left->value = $tmp->value; $tmp->value = $tmp_val; $this->nodeAdjust($left); } } }else echo '不存在子树----'; } } $a = new ATest([3,1,9,2,7,6,11,5,4,13]); $a->run();
执行结果如下：
Array
(
[0] => 13
[1] => 11
[2] => 9
[3] => 7
[4] => 6
[5] => 5
[6] => 4
[7] => 3
[8] => 2
[9] => 1
)
Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 6
[6] => 7
[7] => 9
[8] => 11
[9] => 13
)
程序主要思想如下：
1将给定待排序的数组初始化为节点
2初始化节点，满足大顶堆特点
3最后一个节点的值给到root节点，原来root节点的值输出，释放最后一个节点
4循环执行2，3，直到没有节点可以输出
该方法得到的是降序的排列结果，可以通过array_reverse转换为升序排列
程序里面有很多引用，php小白可能比较懵，大神可能也不屑，哈哈哈