Lowest Common Ancestor of a Binary Search Tree 一.题目描写叙述 二.思路及代码 二叉搜索树有个性质:左子树的值都比根节点小,右子树的值比根节点大.那么我们的思路就是递归比較. 假设输入的两个节点的值比当前节点小,说明是在当前根节点的左子树中:反之则在右子树中. 假设当前根节点比一个大.比一个小.那么第一个出现的这种节点就是近期的父亲节点了. /** * Definition for a binary tree node. * public clas…

Reference: http://blog.csdn.net/v_july_v/article/details/18312089  http://leetcode.com/2011/07/lowest-common-ancestor-of-a-binary-tree-part-ii.html (1) Is the tree a BST or not? BST的话,我们就能按照BST的定义思考了.当前遍历的node如果比我们要找的两个点都大,说明那两个点都在当前node的左边,所以这两个node…

Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example, Given n = 3, your program should return all 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 思路:结果要保留树的所有节点,所以每次都…

1. Unique Binary Search Trees Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 思路:和 Unique Binar…

4.7 Design an algorithm and write code to find the first common ancestor of two nodes in a binary tree. Avoid storing additional nodes in a data structure. NOTE: This is not necessarily a binary search tree. LeetCode上的原题,请参见我之前的博客Lowest Common Ancest…

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题目链接:Validate Binary Search Tree | LeetCode OJ 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…

1.for standard table, it must be sorted by search key. 2.for sorted table , binary search is used automatically when searching with/include table key.  Note:with a binary search (addition BINARY SEARCH is used for standard tables, automatically for s…

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has…

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has…