开始刷题leetcode day3：Balanced Binary Tree

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 of every node never differ by more than 1.

Java

/**
 * Definition for a binary tree node.
 * 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 heightdiff = Math.abs(maxHeight(root.left) - maxHeight(root.right));
        if(heightdiff > 1) return false;
        return (isBalanced(root.left) && isBalanced(root.right));
    }
    
    public int maxHeight(TreeNode root)
    {
        if(root == null) return 0;
        return Math.max(maxHeight(root.left)+1,maxHeight(root.right)+1);
    }
}

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