LeetCode力扣 101. 對稱二叉樹 Symmetric Tree 題解代碼 JavaScript

https://leetcode-cn.com/problems/symmetric-tree/

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {boolean}
 */
function isTreeFun(left, right) {
    if(!left && !right)
        return true;
    if(!left || !right)
        return false;
    if(left.val != right.val)
        return false;
    return isTreeFun(left.left, right.right) && isTreeFun(left.right, right.left);
}

var isSymmetric = function(root) {
    if(!root)
        return true;
    return isTreeFun(root.left, root.right);
};