Balanced Binary Tree

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.

/**
 * 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) {
        int dep;
        return deptree(root,dep);
    }
    //return if balanced
    bool deptree(TreeNode* root,int& dep)
    {
        if(root==NULL)
        {
            dep=0;
            return true;
        }
        int left;
        if(deptree(root->left,left)==false)
            return false;
        int right;
        if(deptree(root->right,right)==false)
            return false;
        dep=left>right?(left+1):(right+1);
        if(left-right>=-1 && left-right<=1)
            return true;
        else
            return false;
    }
};