How to implement binary tree algorithm in PHP-PHP Tutorial-php.cn

This article mainly introduces the method of constructing a binary tree algorithm in PHP. Interested friends can refer to it. I hope it will be helpful to everyone.

Tree is still very important in the data structure. Here, the binary tree is represented by bracket notation. First write a binary tree node class:

// 二叉树节点 class BTNode { public $data; public $lchild = NULL; public $rchild = NULL; public function __construct($data) { $this->data = $data; } }

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Then construct the binary tree:

function CreateBTNode(&$root,string $str) { $strArr = str_split($str); $stack = []; $p = NULL; // 指针 $top = -1; $k = $j = 0; $root = NULL; foreach ($strArr as $ch) { switch ($ch) { case '(': $top++; array_push($stack, $p); $k = 1; break; case ')': array_pop($stack); break; case ',': $k = 2; break; default: $p = new BTNode($ch); if($root == NULL) { $root = $p; } else { switch ($k) { case 1: end($stack)->lchild = $p; break; case 2: end($stack)->rchild = $p; break; } } break; } } }

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here Write a function that prints a binary tree (in-order traversal):

function PrintBTNode($node) { if($node != NULL) { PrintBTNode($node->lchild); echo $node->data; PrintBTNode($node->rchild); } }

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Running result:

Enter a string
"A(B(C,D),G(F))"

The above is the entire content of this article, I hope it will be helpful to everyone's study.

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