2952. Minimum Number of Coins to be Added You are given a 0-indexed integer array coins, representing the values of the coins available, and an integer targe...

Algorithm: Leetcode Contest 372

4 minute read

this contest has 3 problems which related to array-like structure, another 1 problem is bit manipulation, I will ignore this one.

Algorithm: Leetcode Contest 371

2 minute read

From today I will try to participate the Leetcode weekly contest and share my solution here

Algorithm: Dynamic Programming Understanding(2)

4 minute read

Robot Move Issue

Algorithm: Dynamic Programming Understanding(1)

4 minute read

Dynamic Programming would be nightmare for all coders…

Algorithm: Union Find

1 minute read

What is Union Find

Algorithm: Greedy Problems

2 minute read

What is a Greedy Algorithm?

Algorithm: Tree Related Problems

3 minute read

We already explored several problem relating to Trees, in this article I would introduce more typical tree problems

Algorithm: Continue exploring Tree Structure

4 minute read

Given a Tree Node, find its direct successor based different Traversal Type

Data Structure: Tree and its Traversal

4 minute read

Tree

Algorithm: List Related Problems

5 minute read

Data Structure: List

Algorithm: Implement Trie Tree

1 minute read

Trie Tree

Algorithm: Implement my own Heap

1 minute read

Heap

Algorithm: Partition, NetherLandParition and Quick Sort

2 minute read

Partition

Algorithm: Essence of Merge Sort

2 minute read

Merge Sort

Using Array or List to implement Queue & Stack

2 minute read

Stack

System Design

System Design Case Study: Digital Wallet

4 minute read

In digital wallet servce, user can store money in wallet and spend it later.

System Design Case Study: Payment System

4 minute read

A reliable, scalable and flexible payment system is essential.

System Design Case Study: Real Time Leaderboard

3 minute read

In this article we will design a real time leaderboard for an online gaming.

System Design Case Study: Distributed Email System

3 minute read

Let’s design a large-scale distributed email service like Gmail or outlook.

System Design Case Study: Hotel Reservation System

4 minute read

In this article we will discuss how to design a hotel reservation system, actually this design solution is applicable to all booking-related interview topics...

System Design Case Study: Ad Click Aggregation

3 minute read

One core benefit of online advertising is its measurability.

System Design Case Study: Monitoring System

2 minute read

Step1: Scope the problem

System Design Case Study: Google Map

3 minute read

Google maps helps user find directions and navigate to their destination, and it has enormous complexity of google map, it’s important to nail down which fea...

System Design Case Study: Distributed Message Queue

4 minute read

Message queue provide communication and coordination for those building blocks.

System Design Case Study: Yelp

3 minute read

Yelp is a typical app of “proximity service”, which is used to discover nearby place such as restaurant, hotels etc.

System Design Case Study: Nearby Friends

2 minute read

For the opt-in users who grants the permission to access their location, the mobile client present a list of friends who are geographically nearby.

System Design Case Study: Youtube

2 minute read

Everyone knows youtube, it has a very rich features and impossible to cover all of them in a single article.

System Design Case Study: Google Drive

1 minute read

Recently years cloud storage has been more and more popular, google drive is one of the most popular among them, let’s use it as example to understand some d...

System Design Case Study: TypeAhead System

2 minute read

Type Ahead system can also be called “auto-complete” or “incremental search”system etc.

System Design Case Study: Chat System

2 minute read

Step1: Scope the problem

System Design Case Study: News Feed System

2 minute read

What is News Feed?

System Design Case Study: Notification System

1 minute read

A notification system can alert user with important information like breaking news offers.

System Design Case Study: Web Crawler

3 minute read

Step1 : Understanding the problem

System Design Building Block: K-V Store

2 minute read

What is a K-V store?

System Design: Blob Store

3 minute read

What is Blob Store?

System Design: Rate Limiter

4 minute read

What is Rate Limiter?

System Design: Distributed Logging

1 minute read

Why we need logging?

System Design: Distributed Search System

4 minute read

What we need search system?

System Design: Distributed Task Scheduler

2 minute read

What is a task scheduler?

System Design: Building Blocks - Sequencer

1 minute read

Motivation

System Design: Building Blocks - Pub-Sub

2 minute read

What is pub-sub system?

System Design: Building Blocks - Load Balancer

1 minute read

What is Load Balancing

System Design: Building Blocks - Distributed MQ

1 minute read

## Problem

System Design: Building Blocks - Database

4 minute read

I would say, Database is the most important component in a system, when you design a system, and you don’t consider a lot regarding the database, then the de...

System Design: Building Blocks - Cache

2 minute read

Problem

System Design: Building Blocks - CDN

2 minute read

Problem

System Design: General Understanding

4 minute read

System Design is a process of defining components and their integrations, to build a large-scale system that meets the specific set of functional and non-fun...