Every Jack has his Jill.
Every man can expect to have his partner.

Recently, I did some interesting array-related interview questions. The problem description starts like this or similar: Given an array containing numbers in the range and asks you to find duplicate/missing numbers.

Here…


A tree data structure can be defined recursively as a collection of nodes (starting at a root node), where each node is a data structure consisting of value, together with a list of references to nodes (the “children”), with the constraints that no reference is duplicated, and none points to…


I am currently reading the book “RESTful Web Service”, before this I have very limited knowledge about REST to the point that I even don’t know what do those four characters stand for. This article is a brief reading note from Chapter 1 to 4.

REST(Representational State Transfer) is a…


Sliding window technique is useful for solving problems in array or string, especially it is considered as a technique that could reduce the time complexity from O(n²) to O(n).

There are two types of sliding window:

  1. Fixed window length k: the length of the window is fixed and it asks…

Zengrui Wang

Senior Software Engineer @Hulu

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