leetcode98

class Solution {
public:
    vector<int> V;
    void postTree(TreeNode* node) {
        if (node != NULL) {
            if (node->left != NULL) {
                postTree(node->left);
            }
            V.push_back(node->val);
            if (node->right != NULL) {
                postTree(node->right);
            }
        }
    }
    bool isValidBST(TreeNode* root) {
        postTree(root);
        for (int i = 1; i < V.size(); i++) {
            if (V[i] <= V[i - 1]) {
                return false;
            }
        }
        return true;
    }
};

补充一个python的实现：

 1 class Solution:
 2     def __init__(self):
 3         self.lists = []
 4         
 5     def inOrder(self,root):
 6         if root != None:
 7             if root.left != None:
 8                 self.inOrder(root.left)
 9             self.lists.append(root.val)
10             if root.right != None:
11                 self.inOrder(root.right)
12                 
13     def isValidBST(self, root: 'TreeNode') -> 'bool':
14         self.inOrder(root)
15         n = len(self.lists)
16         for i in range(n-1):
17             if self.lists[i] >= self.lists[i+1]:
18                 return False
19         return True

posted on 2018-10-18 19:41 Sempron2800+ 阅读(151) 评论(0) 编辑收藏举报