Curated list of awesome lists
Awesome Algorithms
A curated list of awesome places to learn and/or practice algorithms.
Inspired by awesomeawesomeness and all the other awesome Awesome libraries.
If you want to contribute, please read the contribution guidelines.
Websites
Websites you should use to learn classic algorithms

A Visual Guide to Graph Traversal Algorithms  Interactive visualizations for learning how graph traversal algorithms work.

W3School  Data Structures tutorial.

CodeChef  Learning DSA by practice on Codechef

Algorithm Visualizer  Dozens of animated algorithms (with code), and you can also create your own.

Algorithms Visualization  A dense article on Algorithms Visualization.

BigO Cheat Sheet  BigO complexities of common algorithms used in Computer Science.

CodeDrills  Practice problems recommender (includes Codeforces, Codechef, and Spoj).

CPAlgorithms  Algorithms and data structures are especially popular in the field of competitive programming.

Data Structure Visualizations  Visualize the behavior of Data Structures and play with its operations.

Geeks for Geeks  Lots and lots of wellexplained and implemented algorithms.

Path Finding  A visual representation of how algorithms such as A*, IDA*, BreadthFirstSearch, BestFirstSearch, and others describe a path between two points A and B.

Programiz  Easy to follow tutorials on data structures and algorithms along with suitable examples.

Rosetta Code  A programming chrestomathy site that aims to present implementations of many algorithms and data structures in different programming languages.

Sorting Algorithms  Nice and simple animations of sorting algorithms. With short codes and discussions.

Stoimen's web log  Some algorithms nicely explained.

The Sound of Sorting  The Sound of Sorting  "Audibilization" and Visualization of Sorting Algorithms

VisuAlgo  Visualising data structures and algorithms through animation.

Wikipedia  Algorithms  Of course!!

Wikipedia  Data Structures  and why not ?!!

Learnersbucket  Tutorials on data structures and algorithms in Javascript.

redblobgames  interactive visual explanations of math and algorithms, using motivating examples from computer games.
Youtube Playlists
High Quality Courses and tutorials on youtube
Online Courses
Free and HighQuality Courses Online

Algorithms: Divide and Conquer, Sorting and Searching, and Randomized Algorithms  The primary topics are: asymptotic ("Bigoh") notation, sorting and searching, divide and conquer, and randomized algorithms.

Algorithms: Graph Search, Shortest Paths, and Data Structures  The primary topics are: data structures, graph primitives, and their applications.

Algorithms: Greedy Algorithms, Minimum Spanning Trees, and Dynamic Programming  The primary topics are: greedy algorithms and dynamic programming.

Algorithms: Shortest Paths Revisited, NPComplete Problems and What To Do About Them  The primary topics are: shortest paths, NPcompleteness and what it means for the algorithm designer, and strategies for coping with computationally intractable problems.

Algorithms, Part I  This course covers the essential information that every serious programmer needs to know about algorithms and data structures. Part I covers elementary data structures, sorting, and searching algorithms.

Algorithms, Part II  Part II focuses on graph and stringprocessing algorithms.

Khan Academy Algorithms  Algorithm course ministered by Tomas Cormen and Devin Balkcom.

MIT  6006  Well explained algorithms.

MIT  6046j  Similar to the previous one, but with different algorithms.

MIT  600sc  An easy and wellexplained introduction to algorithms.

MIT 18409  Topics in Theoretical Computer Science: An Algorithmist's Toolkit  It covers a collection of geometric techniques that apply broadly in modern algorithm design.

Udacity Intro to Algorithms  Pythonbased Algorithms course.

Algorithms in Motion  Beginner's algorithms course with fun illustrations, based on the book Grokking Algorithms
 ~~YogiBearian YouTube Channel  Lots of wellexplained videos on various computer science subjects.~~ Account terminated due to violations of Youtube Policies.
Books
The most highly regarded books to learn algorithms
Algorithms and Data structures
Algorithm Analysis
Randomized Algorithms
Cheat Sheets
Github Libraries
Implementations of the most classic algorithms in a wide variety of programming languages
Online Judges
Online Judges to practice what you learned above

A2 Online Judge  Online Judge and problem archive.

ACMICPC Live Archive  Hundreds of problems from previous ACMICPC Regionals and World Finals.

AIZU ONLINE JUDGE  Japanese Online Judge.

Algo Muse  Researchbased algorithmic problems.

AtCoder  Japanese programming contest website.

Baekjoon Online Judge  Korean Online Judge. 10000+ problems. Supports 60+ languages.

CS Academy  Holds online contests and IOI practice contests

CodeChef  More problems and monthly online contests.

Codeforces  The only programming contests Web 2.0 platform

Codefights  Practice programming and tackle your next tech interview

CodeMarshal  Realworld contests online!

CodeWars  A website that houses support to solve algorithms in many languages in varying difficulty.

CoderByte  A decent website with algorithm challenges from beginner to advanced levels. Supports most of the popular languages like C++, python, javascript, ruby.

Firecode  Firecode.io uses machine learning algorithms along with curated realworld interview questions, solutions & a vibrant social community of learners to get you ready for your next coding interview.

Coding Blocks  Website that has problems based on Maths, Data Structures, Various Algorithm and also conducts Coding Competition.

HackerEarth  Practice algorithmic problems & challenges and participate in hiring challenges.

HackerRank  Featured algorithm and functional programming online judges

HiHoCoder  Chinese and English problemsolving practice and recruitment challenge site.

Infoarena  Romanian Online Judge. 1500+ algorithmic problems

Interviewbit  Learn, practice, and prepare for interviews.

Kattis Online judge and problem archive

LavidaOnlineJudge  Korean Online Judge(Half English). 1300+ problems.

Learneroo Algorithms Tutorials  Learn and practice algorithms by solving challenges online.

LeetCode  Learn algorithms and prepare for interviews.

PKU JudgeOnline  Chinese Online Judge.

ProjectEuler  Mathematical problems that can be solved using algorithms (or just a pencil, depending on how much you already know).

Rosalind  A platform for learning bioinformatics and programming through problemsolving.

ShareCode.io  Online Judge and contest host with a lot of algorithmic problems in the archive to practice.

Snakify  An introductory Python course with 100+ algorithmic problems and a stepbystep debugger (from Russia).

SPOJ  More problems.

TopCoder  Lots of problems and realworld/moneyworthy problems in Graphic Design, Data Science, and Development.

Toph  Bangladeshi Online Judge. Holds online contests regularly.

URI  Brazilian Online Judge. Not so many problems, but it's growing and it has online contests.

UVA  Hundreds of problems (from previous ACMICPC Regionals, World Finals, and others).

Codility  Compete to land coding jobs at top companies
Blogs
Awesome list of blogs, mainly for competitive programming but you can refer to these when learning a new topic/algorithm
Some tools that can help you in the learning of algorithms
Related Awesome Lists

Math  Freely available lecture notes on mathematics.

Theoretical Computer Science  The interdisciplinary of Mathematics and Computer Science, Distinguished by its emphasis on mathematical technique and rigour.
License
And for the sake of copyleft, here's our license:
This work is licensed under a Creative Commons Attribution 4.0 International License.