A generic Fisher-Yates Shuffle

It’s been a long time I have done any activity in this blog. I was going through some old stuffs and thought to post something. Today I will post a generic implementation for Fisher-Yates Shuffle.

Although you can get the Fisher-Yates algorithm from wiki, still I am briefly explaining it.

Let us assume that there is a array arr of length n. We need to find a uniformly random permutation of the elements of the array. One of the variations of the algorithm is as follows.

arr is an array of length n, where indexing starts from 0
i=n-1
while i>0
{
  r = generate a random number between 0 and i (both inclusive)
  swap the array elements arr[r] and arr[i]
  i = i - 1
}
arr is now uniformly permuted

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All Combinations Without Repetitions

Problem : To generate all Combinations of a set of distinct elements

Before we start discussing about the implementation we will go through the basic definitions of Combinations. Then we discuss the method to generate all the Combinations with examples and descriptions. Then the source code to implement the method will be presented. Continue reading.

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r-Permutations With Repetitions

Problem : To generate all r-Permutation with repetitions of a set of distinct elements

Before we start discussing about the implementation we will go through the basic definitions of Permutations. Then we discuss the method to generate r-Permutations with repetitions with examples, and at last we implement a C Language Program of the problem. Continue reading.

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Jumble Word Solver


Jumbled Word: A string of characters is given, the task is to find all the meaningful words that can be created by rearranging its letters. Solving a jumble word means to find all the meaningful words that can be made with the initial string.

Objective Of The Article

In this article first we will describe how a jumbled word can be solved and then we present a very simple computer program. After this we present an advanced computer program which will make the solution very fast with the help of a specially designed tree.

Article Revision: 3
Notice 25.9.2009 : This article is undergoing an update and will be made online soon .

Here is another related post Jumbled word solver with C++ and Perl implementation with hash and list: Jumble word solver again.
*Please Note:* This article is very old and lengthy, I am planning for either a revision or a rewrite for the trie tree part which reflect the recent modifications. At the time I wrote this I did not know that the datastructure which I worked out was a trie :) therefore the long explanation.
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