/**
* 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 height(TreeNode* node){
if(node == NULL)
return 0;
int left = height(node->left);
if(left == -1)
return -1;
int right = height(node->right);
if(right == -1)
return -1;
if(abs(left-right)>1)
return -1;
else
return max(left, right)+1;
}
bool isBalanced(TreeNode* root) {//左右子树是平衡二叉树,且高度差不超过1
int result = height(root);
if(result == -1)
return false;
else
return true;
}
};
判断一个树是不是二叉树->判断一个树的高度
height == -1 左右子树不是平衡二叉树,或者高度差大于1
height == 0 空树
height == 非0,真实的高度