[LeetCode]Balanced Binary Tree

题目描述:(链接)

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.

解题思路:

/**
* 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 height(root) >= 0;
}

int height(TreeNode *root) {
if (root == nullptr) return 0;

int left = height(root->left);
int right = height(root->right);

if (left < 0 || right < 0 || abs(left - right) > 1) {
return -1;
}

return max(left, right) + 1;
}
};