Leetcode 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.

判断一个二叉树是否为平衡二叉树，主要看左子树和右子树的深度绝对值查是否小于等于1。这里用递归的方法来解决。

/**
* 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 depthleft = getdepth(root->left,1);
int depthright = getdepth(root->right,1);
if(abs(depthleft-depthright) > 1)
{
return false;
}
else
{
return isBalanced(root->left)&&isBalanced(root->right);
}
}

int getdepth(TreeNode* root,int depth)
{
if(root==NULL)
{
return depth;
}
else
{
return max(getdepth(root->left,depth+1),getdepth(root->right,depth+1));
}
}
};