#110 Balanced Binary Tree.cpp

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool isBalanced(TreeNode* root) {
        if(!root) {
            return true;
        }
        return isBalanced(root->left) && isBalanced(root->right) && abs(findHeight(root->left) - findHeight(root->right)) < 2;
    }
    
private:
    int findHeight(TreeNode* node) {
        if(!node) {
            return 0;
        }
        return 1 + max(findHeight(node->left), findHeight(node->right));
    }
};