Height 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.

Ans:

public boolean isBalanced(TreeNode root) {
     
        if(root == null) {
            return true;
        }
        int lHeight = -1, rHeight = -1;
        if(root.left != null) {
            lHeight = height(root.left);
        }
     
        if(root.right != null) {
            rHeight = height(root.right);
        }
        if(Math.abs(lHeight-rHeight)>1) {
            return false;
        }
        return isBalanced(root.left)&&isBalanced(root.right);
    }
 
    private int height(TreeNode T) {
        if(T == null) {
            return -1;
        }
        if(T.left==null && T.right==null) {
            return 0;
        }
        return Math.max(height(T.left),height(T.right))+1;
    }