Implement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST.
Calling next() will return the next smallest number in the BST.
Example:
BSTIterator iterator = new BSTIterator(root); iterator.next(); // return 3 iterator.next(); // return 7 iterator.hasNext(); // return true iterator.next(); // return 9 iterator.hasNext(); // return true iterator.next(); // return 15 iterator.hasNext(); // return true iterator.next(); // return 20 iterator.hasNext(); // return false
Note:
next() and hasNext() should run in average O(1) time and uses O(h) memory, where h is the height of the tree. You may assume that next() call will always be valid, that is, there will be at least a next smallest number in the BST when next() is called.
Problem2 (https://leetcode.com/problems/reorder-list/)
Given a singly linked list L: L0→L1→…→Ln-1→Ln, reorder it to: L0→Ln→L1→Ln-1→L2→Ln-2→…
You may not modify the values in the list's nodes, only nodes itself may be changed.
Example 1:
Given 1->2->3->4, reorder it to 1->4->2->3. Example 2:
Given 1->2->3->4->5, reorder it to 1->5->2->4->3.
You are given a pointer/ reference to the node which is to be deleted from the linked list of N nodes. The task is to delete the node. Pointer/ reference to head node is not given.
Note: No head reference is given to you.
Input Format: First line of input contains number of testcases T. For each testcase, first line of input contains length of linked list and next line contains the data of the linked list. The last line contains the node to be deleted.
Output Format: For each testcase, in a newline, print the linked list after deleting the given node.
Your Task: This is a function problem. You only need to complete the function deleteNode that takes reference to the node that needs to be deleted. The printing is doneautomatically by the driver code.
Constraints: 1 <= T <= 100 1 <= N <= 103
Example: Input: 2 2 1 2 1 4 10 20 4 30 20
Output: 2 10 4 30
Explanation: Testcase 1: After deleting 20 from the linked list, we have remaining nodes as 10, 4 and 30
Write a program to find the node at which the intersection of two singly linked lists begins.
For example, the following two linked lists:
begin to intersect at node c1.
Example 1:
Input: intersectVal = 8, listA = [4,1,8,4,5], listB = [5,0,1,8,4,5], skipA = 2, skipB = 3 Output: Reference of the node with value = 8 Input Explanation: The intersected node's value is 8 (note that this must not be 0 if the two lists intersect). From the head of A, it reads as [4,1,8,4,5]. From the head of B, it reads as [5,0,1,8,4,5]. There are 2 nodes before the intersected node in A; There are 3 nodes before the intersected node in B. Example 2:
Input: intersectVal = 2, listA = [0,9,1,2,4], listB = [3,2,4], skipA = 3, skipB = 1 Output: Reference of the node with value = 2 Input Explanation: The intersected node's value is 2 (note that this must not be 0 if the two lists intersect). From the head of A, it reads as [0,9,1,2,4]. From the head of B, it reads as [3,2,4]. There are 3 nodes before the intersected node in A; There are 1 node before the intersected node in B. Example 3:
Input: intersectVal = 0, listA = [2,6,4], listB = [1,5], skipA = 3, skipB = 2 Output: null Input Explanation: From the head of A, it reads as [2,6,4]. From the head of B, it reads as [1,5]. Since the two lists do not intersect, intersectVal must be 0, while skipA and skipB can be arbitrary values. Explanation: The two lists do not intersect, so return null.