Balanced Binary Tree

    public boolean isBalanced(TreeNode root) {        // Start typing your Java solution below        // DO NOT write main() function        if(getHeight(root) == -1) return false;        return true;    }        public int getHeight(TreeNode root) {        if(root == null) return 0;        int leftHeight = getHeight(root.left);        if(leftHeight == -1) return -1;        int rightHeight = getHeight(root.right);        if(rightHeight == -1) return -1;        if(Math.abs(leftHeight - rightHeight) > 1)return -1;        return Math.max(leftHeight, rightHeight) + 1;    }