LeetCode（110） Balanced Binary Tree

题目

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.

分析

判断给定二叉树是否为二叉平衡树，即任一节点的左右子树高度差必须小于等于1，只需要求得左右子树的高度，比较判定即可。

AC代码

class Solution {
public:
//判断二叉树是否平衡
bool isBalanced(TreeNode* root) {
if (!root)
return true;

int lheight = height(root->left), rheight = height(root->right);

if (abs(lheight - rheight) <= 1)
return isBalanced(root->left) && isBalanced(root->right);
else
return false;
}
//求树的高度
int height(TreeNode *root)
{
if (!root)
return 0;
else
return max(height(root->left), height(root->right)) + 1;
}
};

GitHub测试程序源码