LeetCode 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.

Solution 1:

public class Solution {
    public boolean isBalanced(TreeNode root) {
        if (root == null) return true;
        if (Math.abs(maxdeep(root.left) - maxdeep(root.right)) > 1) return false;
       
        return isBalanced(root.left)&&isBalanced(root.right);
    }
    public int maxdeep(TreeNode root){
         if (root == null) return 0;

          return Math.max(maxdeep(root.left), maxdeep(root.right)) + 1;
        
    }
    
} 

Time Complexity: O(n^2)

Solution 2:

public class Solution {
    public boolean isBalanced(TreeNode root) {
        return BackOrderT(root) > -1;
    }
    
    public int BackOrderT(TreeNode root){
        if (root == null) return 0;
        int leftDep = BackOrderT(root.left);
        int rightDep = BackOrderT(root.right);
        if ( (Math.abs(leftDep - rightDep) > 1)||(leftDep == -1)||(rightDep == -1) ) return -1;
        return Math.max(leftDep + 1, rightDep + 1);
        
    }
    
}

Time Complexity: O(n)