【LeetCode】Balanced Binary Tree

/**
 * 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) {
        if(root == NULL)
            return true;
        if(isBalanced(root->left) && isBalanced(root->right))
        {
            int left = height(root->left);
            int right = height(root->right);
            if(fabs(left-right) <= 1)
                return true;
            else
                return false;
        }
        else 
            return false;
    }
    int height(TreeNode* root)
    {
        if(root == NULL)
            return 0;
        int left = height(root->left);
        int right = height(root->right);
        return max(left,right)+1;
    }
};