PHP method to determine whether a binary tree is symmetrical

This article explains how PHP determines whether a binary tree is symmetrical.

The example in this article describes the method of determining whether a binary tree is symmetrical in PHP. Share it with everyone for your reference, the details are as follows:

Question

Please implement a function to determine whether a binary tree is symmetrical. Note that a binary tree is defined as symmetric if it is the same as the image of the binary tree.

Solution

Recursively judge both sides of the binary tree.

Implementation code:

/*class TreeNode{ 
var $val; 
var $left = NULL;
var $right = NULL; 
function __construct($val){ 
$this->val = $val; 
} 
}*/ 
function isSymmetrical($pRoot) 
{ 
if($pRoot==null) return true; 
return compare($pRoot->left,$pRoot->right); 
}
function compare($root1,$root2){
 
if($root1==null&&$root2==null) return true;
 
if($root1==null||$root2==null) return false;
 
if($root1->val!=$root2->val) return false;
 
return compare($root1->left,$root2->right)&&compare($root1->right,$root2->left);
 
}

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