This week we will try to solve the leetcode problem 724, find the pivot index. Given an array of integers (nums), calculate the pivot index of the nums array. The pivot index is the index where the sum of all the numbers strictly to the left of the index is equal to the sum of all the numbers strictly to the index’s right. Below are some examples.

Going into the questions, we don’t know if there are multiple ways (or one optimal way) to solve the problem, so we will try to draw out the brute force method first.


This week will try to solve the leetcode question substrings of size three with distinct characters. For this problem we want to go through every 3 character substrings and see how many have of these substrings have 3 non repeating/unique characters.

Before we think of any methods we can use, let us break down the problem.


What is depth-first search?

Depth-first search (DFS) is an algorithm for traversing or searching tree or graph data structures. One starts at the root (selecting some arbitrary node as the root in the case of a graph) and explores as far as possible along each branch before backtracking.


This week we will be going through leetcode (problem 144) and try to solve the binary tree preorder traversal problem. Before we start off, let us briefly go over the properties of a binary search tree(BST) again. In a BST, we alway start at the root(a parent node) with two child nodes. The left child node (and any of its childrens) has to and will always be less than the parent, and the right child node (and any of its childrens) has to and will always be greater than the parent.


An API is a set of definitions and protocols for building and integrating application software. API stands for application programming interface.

APIs let your product or service communicate with other products and services without having to know how they’re implemented. This can simplify app development, saving time and money. When…


In our previous article, we learned that Catalan numbers is a sequence of infinite numbers with its own property. We also went through some questions or examples that would use Catalan numbers to provide the answer. Just like square numbers or Fibonacci numbers, Catalan Numbers has its own sequence pattern…


What are Catalan numbers? To put it shortly, Catalan numbers is a sequence of infinite numbers with its own property. In mathematics, we have different sequence of number patterns that we’ve all have come across. Of course no other sequence would be possible with out our basic counting numbers sequence(1,2,3,4,5…)…


This week will take a look at a popular leetcode problem and try to solve it with a data structure that we are familiar with. This question is extremely relevant to every day coding. Anyone who has touched a code editor knows the frustration and the feeling of missing a…


On one of my previous posts, we dived in to the topic of asynchronous vs synchronous. This week, we’ll look at a few other core topics and refresh our knowledge of Javascript.

Classes & Object

According to MDN Web Docs, classes are are a template for creating objects. They encapsulate data with code…


Palindromes | semordnilaP

Going through algorithms and practice questions, we all have come across a palindrome or two. If you haven’t, you will run in to one soon. So what is a palindrome you ask?

A palindrome is a word, phrase, number or a sequence of characters that reads the same backward or…

Johnson Liu

Software Engineer

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