110. 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.
题目大意：
判断一颗二叉树是否为平衡二叉树。
思路：
-
做一个辅助函数来求的树的高度。
-
通过辅助函数来递归求解。
代码如下：
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/**
* 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
:
int
depth(TreeNode* root)
{
if
(!root)
return
0;
int
l = depth(root->left) ;
int
r = depth(root->right) ;
return
1 + ((l > r)?l:r);
}
bool
isBalanced(TreeNode* root) {
if
(!root)
return
true
;
else
{
int
l = depth(root->left);
int
r = depth(root->right);
if
(l + 1 < r || r + 1 <l)
{
return
false
;
}
else
return
(isBalanced(root->left) && isBalanced(root->right) );
}
}
};
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本文转自313119992 51CTO博客，原文链接:http://blog.51cto.com/qiaopeng688/1835477
