Balanced Binary Tree [LeetCode]

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.

Solution: 

     bool helperBalanced(int *depth, TreeNode * root){
         if(root->left == NULL && root->right == NULL){
             (*depth) = ;
             return true;
         }

         int left_depth = ;
         int right_depth = ;
         if(root->left != NULL){
             if(helperBalanced(&left_depth, root->left) == false)
                 return false;
         }

         if(root->right != NULL){
             if(helperBalanced(&right_depth, root->right) == false)
                 return false;
         }

         if(abs(right_depth - left_depth) > )
             return false;

         (*depth) = max(left_depth, right_depth) + ;

         return true;
     }

     bool isBalanced(TreeNode *root) {
         if(root == NULL)
             return true;
         int depth= ;
         return helperBalanced(&depth, root);
     }