Calvin Chan – Medium

Mar 16, 2019

Solving Basic Calculator I, II, III on leetcode

Recently, I found that there are 3 questions on leetcode look very similar and I am going to discuss them today and the ways that I solved the questions. Those questions are Basic Calculator I, Basic Calculator II, Basic Calculator III The questions look easy at first, it seems that…

Programming

4 min read

Jan 5, 2019

Letter Combinations of a Phone Number

Two years ago, during a FAANG coding interview, I was asked to print all the possible letter combinations of a phone number. I was shocked and I tried very hard during the interview but I gave up eventually. …

Programming

2 min read

Jan 5, 2019

A general approach to Subsets, Combinations, and Permutations

Recently, I found that there are 5 questions on leetcode look very similar and I am going to discuss today and my way to solve the questions. These questions are Subsets, Subsets II, Combinations, Permutations and Permutations II At my first glance, these questions could be solved by several for-loops…

Backtracking

3 min read

A general approach for Subsets, Combinations and Permutations

Sep 20, 2018

How to find the starting/ending position of an element using Binary Search

Binary search is a fundamental algorithm in computer science. It looks easy(at first), but have you ever encountered these problems when you want to change a litter bit the algorithm to search for the boundaries… You have no idea how to make it works…whats wrong?🤯 Before we go further, let’s do a warm-up with the most basic and elementary form of binary search.

Programming

5 min read

How to find the starting/ending position of an element using Binary Search

Mar 20, 2017

Deploy a React + React Router+ Redux website on S3

Deploy a React + React Router+ Redux website on S3 Just 4steps Create a S3 Bucket Upload all the static files Edit Bucket Policy https://docs.aws.amazon.com/AmazonS3/latest/dev/example-bucket-policies.html Enable Static Website If the website has other languages(i18n), to avoid mojibake, remember set the content type of index.html to text/html; charset=UTF-8 or set <meta charset='utf-8'> in document <head>

React

1 min read

Jun 22, 2016

A Trick to Play a Landscape Video in a Portrait ViewController Regardless of Orientation Lock

If your ViewController(which plays videos) can be in both portrait and landscape, I strongly recommend that to do it with AutoLayout and ignore this post. ***But if you wanna know how to do it with AutoLayout as well, checkout out my repo, change the storyboard entry point to RotatingViewController*** I’m…

I OS

2 min read

Jun 2, 2016

The simplest way to make a pull-to-refresh and infinite tableview with ReactJS

Pull-to-refresh and pull-to-load-more are extremely common to show data in web, there are so many libraries to make it in React, but there are some problems.😩 Most of them are difficult to subclass, you need to use their component to render the cells. …

Java Script

3 min read

The simplest way to make a pull-to-refresh and infinite tableview with ReactJS