PHP实现二叉树的深度优先与广度优先遍历方法_php技巧

本文实例讲述了PHP实现二叉树的深度优先与广度优先遍历方法。分享给大家供大家参考。具体如下：

#二叉树的广度优先遍历
#使用一个队列实现
class Node {
 public $data = null;
 public $left = null;
 public $right = null;
}
#@param $btree 二叉树根节点
function breadth_first_traverse($btree) {
 $traverse_data = array();
 $queue = array();
 array_unshift($queue, $btree); #根节点入队
 while (!empty($queue)) { #持续

输出节点，直到队列为空 $cnode = array_pop($queue); #队尾元素出队 $traverse_data[] = $cnode->data; #左节点先入队，然后右节点入队 if ($cnode->left != null) array_unshift($queue, $cnode->left); if ($cnode->right != null) array_unshift($queue, $cnode->right); } return $traverse_data; } #深度优先遍历,使用一个栈实现 function depth_first_traverse($btree) { $traverse_data = array(); $stack = array(); array_push($stack, $btree); while (!empty($stack)) { $cnode = array_pop($stack); $traverse_data[] = $cnode->data; if ($cnode->right != null) array_push($stack, $cnode->right); if ($cnode->left != null) array_push($stack, $cnode->left); } return $traverse_data; } $root = new Node(); $node1 = new Node(); $node2 = new Node(); $node3 = new Node(); $node4 = new Node(); $node5 = new Node(); $node6 = new Node(); $root->data = 1; $node1->data = 2; $node2->data = 3; $node3->data = 4; $node4->data = 5; $node5->data = 6; $node6->data = 7; $root->left = $node1; $root->right = $node2; $node1->left = $node3; $node1->right = $node4; $node2->left = $node5; $node2->right = $node6; $traverse = breadth_first_traverse($root); print_r($traverse); echo ""; $traverse = depth_first_traverse($root); print_r($traverse);

希望本文所述对大家的php程序设计有所帮助。