Validate Binary Search Tree
Given a binary tree, determine if it is a valid binary search tree (BST).
Assume a BST is defined as follows:
- The left subtree of a node contains only nodes with keys less than the node's key.
- The right subtree of a node contains only nodes with keys greater than the node's key.
- Both the left and right subtrees must also be binary search trees.
confused what "{1,#,2,3}"
means? > read more on how binary tree is serialized on OJ.
/** * 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: void _inOrder(TreeNode* root, vector<int> &res) { if (NULL == root) { return; } _inOrder(root->left, res); res.push_back(root->val); _inOrder(root->right, res); } bool isValidBST(TreeNode* root) { vector<int> res; _inOrder(root, res); int i; for (i = 1; i< res.size(); i++) { if (res[i] <= res[i - 1]) { return false; } } return true; } };
posted on 2016-02-08 16:07 walkwalkwalk 阅读(131) 评论(0) 编辑 收藏 举报