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.

Balanced Binary Tree.cpp

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool isBalanced(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(root == NULL) {
            return true;
        }
        
        if(getHeight(root) == -1) {
            return false;
        } else {
            return true;
        }
    }
    
    
    int getHeight(TreeNode* root) {
        if(root == NULL) {
            return 0;
        } else {
            int left = getHeight(root->left);
            int right = getHeight(root->right);
            
            if(left == -1 or right == -1) {
                return -1;
            }
            
            if(abs(left - right) > 1) {
                return -1;
            } else {
                return max(left, right) + 1;
            }
            
        }
    }
};