Online PHP editor | output for ro1oV

<?php class Node { public $data = null; public $parent = null; public $left = null; public $right = null; } #使用数组构造完全二叉树 function build_cbtree($a) { $root = new Node(); $root->data = $a[0]; for ($i = 1; $i < count($a); $i++) { $node = new Node(); $node->data = $a[$i]; insert_node($root, $node); } return $root; } #插入完全二叉树节点 function insert_node($root, $inode) { #使用树的广度优先遍历顺序取出节点，直到找到第一个左右子节点没满的节点，将待插入节点插入节点左边或右边 $queue = array(); array_unshift($queue, $root); while (!empty($queue)) { $cnode = array_pop($queue); if ($cnode->left == null) { $cnode->left = $inode; $inode->parent = $cnode; return $root; } else { array_unshift($queue, $cnode->left); } if ($cnode->right == null) { $cnode->right = $inode; $inode->parent = $cnode; return $root; } else { array_unshift($queue, $cnode->right); } } return $root; } #树的广度优先遍历 function bf_traverse($root) { $queue = array(); array_unshift($queue, $root); while (!empty($queue)) { $cnode = array_pop($queue); echo $cnode->data . " "; if ($cnode->left !== null) array_unshift($queue, $cnode->left); if ($cnode->right !== null) array_unshift($queue, $cnode->right); } echo "<br>"; } $a = array(9, 8, 7, 6, 8, 4, 3, 2, 1); $root = build_cbtree($a); bf_traverse($root); #广度优先遍历 ?>