题目描述
Given a binary tree, determine if it is height-balanced.
For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees ofeverynode never differ by more than 1.
我的思路：采用最笨的办法，递归的判断一棵树的左子树和右子树分别是不是平衡二叉树。
/**
* Definition for binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public boolean isBalanced(TreeNode root) {
if (root == null)
return true;
int ldepth = height(root.left);
int rdepth = height(root.right);
if (Math.abs(ldepth - rdepth) > 1)
return false;
boolean ltree = isBalanced(root.left);
boolean rtree = isBalanced(root.right);
return ltree & rtree;
}
public int height(TreeNode node){
if (node == null)
return 0;
int ldepth = height(node.left);
int rdepth = height(node.right);
return ldepth > rdepth?ldepth + 1:rdepth + 1;
}
}
