This problem was asked at Intuit
Design a parking lot system where you need to provide a token with the parking space number on it to each new entry for the space closest to the entrance. When someone leave you need update this space as empty. What data structures will you use to perform the closest empty space tracking, plus finding what all spaces are occupied at a give time.
https://leetcode.com/problems/copy-list-with-random-pointer/
A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.
Return a deep copy of the list.
The Linked List is represented in the input/output as a list of n nodes. Each node is represented as a pair of [val, random_index] where:
val: an integer representing Node.val random_index: the index of the node (range from 0 to n-1) where random pointer points to, or null if it does not point to any node.
Example 1:
Input: head = [[7,null],[13,0],[11,4],[10,2],[1,0]] Output: [[7,null],[13,0],[11,4],[10,2],[1,0]] Example 2:
Input: head = [[1,1],[2,1]] Output: [[1,1],[2,1]] Example 3:
Input: head = [[3,null],[3,0],[3,null]] Output: [[3,null],[3,0],[3,null]] Example 4:
Input: head = [] Output: [] Explanation: Given linked list is empty (null pointer), so return null.
Constraints:
-10000 <= Node.val <= 10000 Node.random is null or pointing to a node in the linked list. Number of Nodes will not exceed 1000.