Check is BT is balanced -- Leetcode

Question:

Answer:
1. My code :
  /**
 * 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) return true;
     
   else if(!isBalanced(root->left) || !isBalanced(root->right)) return false;

   int height1 = height(root -> left);
   int height2 = height(root -> right);
   if (abs(height1-height2) <= 1) return true;
   else return false;
}
 
int height(TreeNode *root){
    if(!root) return 0;
    else return max(height(root->left),height(root->right)) + 1;
}
};

2.Code online:
/******Better!*******/
class Solution {
public:
    bool isBalanced(TreeNode *root) {    
      if(root == NULL) return true;
      int val = GetBalance(root);
      if(val ==-1) return false;
      return true;        
       
    }  
    int GetBalance(TreeNode* node) {
      if(node == NULL)
        return 0;
      int left = GetBalance(node->left);
      if(left == -1) return -1;
      int right = GetBalance(node->right);
      if(right == -1) return -1;
      if(left-right>1 || right-left>1)
        return -1;
      return left>right? left+1:right+1;
    }  
};