Simple algorithm tutorials?

Question

I want to learn algorithms using some very basic simple tutorials. Are there any out there? I have heard of recursion and stuff and I would like to get good at it. Any help would be appreciated.

Answer 1

MIT's OCW has video lectures of their Algorithm course. The professor is one of the authors of the book Introduction to Algorithms, which another poster suggested.

It assumes a basic knowledge of Discrete Maths.

Answer 2

Recursion is a language feature, and less an "algorithm" per se. All recursion can be replaced with proper data structures (like a stack).

I'd recommend grabbing a book. The problem with algorithms is that it's a relatively progressive topic. You first need to learn simple searches before you can learn sorting, and you need sorting before you can do minimum spanning trees etc. A book will properly order these, and if the text doesn't give you enough information the internet is a great next step. Try Amazon and look at the comments for someone who is new.

Make sure you learn an implementation language before you try to go at this though, until you understand how the language works it's going to be very hard to pick out bugs in your logic vs a misunderstanding of what's happening for a given sequence of commands.

Answer 3

I would start out by taking a look at EternallyConfuzzled which contains great tutorials for basic Data Structures an Algorithms including linked lists and binary search trees, sorting and searching algorithms. If you want to learn more after this I would recommend the following books in order of increasing complexity, completeness, and required math knowledge:

• Algorithms in C (also available in C++ and Java)
• Introduction to Algorithms
• The Art of Computer Programming

Answer 4

Recursion really isn't an algorithm. Since you don't have anything specific you're interested in I'd suggest you read wikipedia's List of alorithms or as others have suggested grab a book.

Answer 5

I suggest that you start from sorting algorithms. Read the related wikipedia page, skip the O(n log n) stuff, and focus on the implementations of, say, insertion sort, merge sort, and quick sort. Familiarize with binary searching. Also, learn about some basic data structures, such as vectors, linked lists, stacks, their implementation, and what they are useful for. (More often than not, an algorithm to solve a problem goes together with a suitable data structure.) Once you are confident with different algorithms and data structures, you can dive in a more complete treatise such as the book by Cormen et al.

As for recursion, it is not an algorithm in itself. It is instead a technique that some algorithms employ to solve a problem, when the latter can be naturally split into subproblems. The technique of splitting a problem, solving the subproblems separately and then merging their solutions to obtain a solution for the original problem, is called "divide et impera", or "divide and conquer". (Recursion is also the related feature of most programming languages, where it basically means "functions that call themselves".)

The most cited, the most trivial, and the most useless example of a "recursive algorithm", is the one to compute factorials. Don't mind it. Instead, read about the Tower of Hanoi problem, which admits a simple and elegant recursive solution, and again, study some sorting algorithms, for many of them are indeed recursive.

Answer 6

I would start at the Stony Brook Algorithm Repository. The site has some really good explanations of different types of algorithms, and it references what books and other resources it uses so you can get a taste of what's available.

Answer 7

USA Computing Olympiad has a nice algorithms training site that so far anyone can sign up for and it's almost in a class like format. read a little, do an exercise, read more, do an exercise etc.

Answer 8

To the various people who have commented that book xyz is not simple, I'd point out that algorithmics is not a simple topic. You need at least university entry level mathematics to understand the concepts plus the ability to reason about computation at a suitably abstract level. If you ever find an "Algorithmics for Dummies" book, don't waste your money!

Answer 9

One of my favorite list of algorithm problems is Project Euler, they are pretty diverse and you can solve the same problem many times for optimizations, and you will find lots of communities (C++, C#, Python, ... etc) posting their benchmarks for every problem

It is so much fun, geek fun

Answer 10

TopCoder has some good algorithm tutorials.

Answer 11

Algorithmatic.com is good too.