/**
* Definition for binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public boolean isSymmetric(TreeNode root) {
if(root==null){
return true;
}
LinkedList<TreeNode> queue = new LinkedList<TreeNode>();
LinkedList<TreeNode> childrenQueue = new LinkedList<TreeNode>();
queue.add(root);
while (!queue.isEmpty()){
TreeNode node = queue.remove();
if(node==null || node.left==null){
childrenQueue.add(null);
}else{
childrenQueue.add(node.left);
}
if(node==null || node.right==null){
childrenQueue.add(null);
}else{
childrenQueue.add(node.right);
}
if(queue.isEmpty() && !childrenQueue.isEmpty()){
for(int i=0; i<childrenQueue.size(); i++){
if(childrenQueue.get(i)!=null){
queue.add(childrenQueue.get(i));
}
if(i<childrenQueue.size()/2){
int j = childrenQueue.size()-i-1;
if(childrenQueue.get(i)==null && childrenQueue.get(j)==null){
continue;
}
if((childrenQueue.get(i)==null && childrenQueue.get(j)!=null) || (childrenQueue.get(i)!=null && childrenQueue.get(j)==null)){
return false;
}
if(childrenQueue.get(i).val == childrenQueue.get(j).val){
continue;
}
return false;
}
}
childrenQueue.clear();
}
}
return true;
}
}
分享到：
相关推荐
java java_leetcode-101-symmetric-tree
Symmetric tree - Java Recursive - Java Iterative - C Recursive - Python Iterative 0102 Binary Tree Level Order Traversal - Python3 iterative 0103 Binary Tree Zigzag Level Order Traversal - ...
例如，树的层级遍历（Levelorder Traversal）、判断树的对称性（Symmetric Tree）、找到二叉搜索树中距离某个值最近的节点（Closest Binary Search Tree Value）等。这些题目通常要求编写者熟悉树的结构和遍历方法，...
- **Symmetric Tree**：判断一个二叉树是否是对称的。 - **Same Tree**：判断两棵二叉树是否相同。 - **Balanced Binary Tree**：判断一个二叉树是否是平衡的。 - **Path Sum**：判断是否存在一条路径，其节点值...
Leetcode 使用 Javascript 的解决方案Leetcode Problems and interview problems in Javascript10 Regular Expresion Matching.js100 Same Tree.js101 Symmetric Tree.js102 Binary Tree Level Order Traversal.js...