LeetCode刷题（C++）——Balanced Binary Tree（Easy）

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 a binary tree node.
 * 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;
        int depth=0;
        return isBalanced(root,depth);
    }
    
    bool isBalanced(TreeNode* pRoot, int& pDepth)
    {
        if(pRoot==NULL)
        {
            pDepth = 0;
            return true;
        }
        int left, right;
        if(isBalanced(pRoot->left,left)&&isBalanced(pRoot->right,right))
        {
            int diff = abs(left-right);
            if(diff<=1&&diff>=-1)
            {
                pDepth = 1+(left>right?left:right);
                return true;
            }
        }
        return false;
    }
};