LeetCode之“树”：Balanced Binary Tree

　　题目链接

　　题目要求：

　　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.

　　这道题难度还好。具体程序（16ms）如下：

 /**
  * 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) {
         return isBalancedSub(root);
     }

     bool isBalancedSub(TreeNode *tree)
     {
         if(!tree)
             return true;
         if(abs(getHeight(tree->left) - getHeight(tree->right)) > )
             return false;
         return isBalancedSub(tree->left) && isBalancedSub(tree->right);
     }

     int getHeight(TreeNode *tree)
     {
         if(!tree)
             return ;

         int m = getHeight(tree->left);
         int n = getHeight(tree->right);
         return (m > n) ? m +  : n + ;
     }
 };