How to Design a First Unique Number Class with O(1)?
You have a queue of integers, you need to retrieve the first unique integer in the queue. Implement the FirstUnique class: FirstUnique(int nums) Initializes the object with the numbers …
Tag: data structure
How to Print Immutable Linked List in Reverse using Recursion or Stack?
You are given an immutable linked list, print out all values of each node in reverse with the help of the following interface: ImmutableListNode: An interface of immutable linked …
Algorithm to Find Duplicate Files in System using Hash Map
Given a list of directory info including directory path, and all the files with contents in this directory, you need to find out all the groups of duplicate files …
The C++ Function using STL to Check Duplicate Elements/Characters in Array/Vector/String
Let’s say we want to implement a C++ function based on STL containers to check if a given string contains duplicate characters, or a given vector/array contains duplicate elements. …
The Monotone Queue Implementation in Python
A queue is a first-in-first-out (FIFO) data structure. We all know that the list/array in Python is very powerful, that it can be used as a queue itself. For …