LeetCode 101. 数据结构->对称二叉树(递归同时判断左子树和右子树节点
原题链接
简单
作者:
JustDoIt11
,
2023-10-31 12:37:02
,
所有人可见
,
阅读 35
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
public boolean isSymmetric(TreeNode root) {
if (root.left == null && root.right != null || root.left != null && root.right == null) return false;
if (root.left == null && root.right == null) return true;
return dfs(root.left, root.right);
}
public boolean dfs(TreeNode l, TreeNode r) {
if (l == null && r == null) return true;
if (l == null && r != null) return false;
if (l != null && r == null) return false;
return l.val == r.val && dfs(l.right, r.left) && dfs(l.left, r.right);
}
}