permutation

permutations gone wrong

I have written code to implement an algorithm I found on string permutations. What I have is an arraylist of words ( up to 200) and I need to permutate the list in levels of 5. Basically group the string words in fives and permutated them. What I have takes the first 5 words generates the permutations and ignores the rest of the arraylis...

Is it possible to enumerate for all permutations of two IEnumerables using linq

I could do this using loops, but is there a way to take two IEnumerables, enumerate through all possible permutations and select an object that contains the permutation? I feel like this 'should' be possible but am not really sure what operators to use. Thanks James ...

How can I ensure that when I shuffle my puzzle I still end up with an even permutation?

I'm interested making an implementation of the 14-15 puzzle: I'm creating an array with the values 0 - 15 in increasing order: S = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 } Now, what I want to do is shuffle them to create a new instance of the puzzle. However, I know that if I create a board with an "odd permutation" ...

How can I generate all possible permutations from a Perl regular expression?

I know you can generate all permutations from a list, using glob or Algorithm::Permute for example - but how do you generate all possible permutations from a regular expression? I want to do like: @perms = permute( "/\s[A-Z][0-9][0-9]/" ); sub permute( $regex ) { # code - put all permutations of above regex in a list return @l...

Graph and permutation problem

I have a graph (with nodes and edges) containing symmetry and a group of permutations to label the nodes so no edges are changed (automorphisms). Now I would like to determine for which nodes a permutation exchanges two equivalent (i.e. nodes with the same color or symmetry class) neighboring nodes. When the nodes with equivalent neighb...

Given an array of integers [x0 x1 x2], how do you calculate all possible permutations from [0 0 0] to [x0 x1 x2]?

I am writing a program that takes in an ArrayList and I need to calculate all possible permutations starting with a list of zeroes, up to the value in the corresponding input list. Does anyone know how to iteratively calculate these values? For example, given [ 1 2 ] as input, it should find and store the following lists: [0 0], [1 0]...

[C++] next_permutation for combinations or subsets in powerset

Is there some equivalent library or function that will give me the next combination of a set of values like next_permutation in does for me? ...

Permutations in python 2.5.2

Hi, I have a list of numbers for input, e.g. 671.00 1,636.00 436.00 9,224.00 and I want to generate all possible sums with a way to id it for output, e.g.: 671.00 + 1,636.00 = 2,307.00 671.00 + 436.00 = 1,107.00 671.00 + 9,224.00 = 9,224.00 671.00 + 1,636.00 + 436.00 = 2,743.00 ... and I would like to do it in Python My current...

Algorithm to generate all possible permutations of a list?

Say I have a list of n elements, I know there are n! possible ways to order these elements. What is an algorithm to generate all possible orderings of this list? Example, I have list [a, b, c]. The algorithm would return [[a, b, c], [a, c, b,], [b, a, c], [b, c, a], [c, a, b], [c, b, a]]. I'm reading this here http://en.wikipedia.org/wi...

Multiple range product in Python

Is there a better way to do this: perms = product(range(1,7),range(1,7),range(1,7)) so that I can choose how many ranges I use? I want it to be equivalent to this, but scalable. def dice(num) if num == 1: perms = ((i,) for i in range(1,7)) elif num == 2: perms = product(range(1,7),range(1,7)) elif num == 3...

The algorithm used to generate recommendations in Google News?

Hi everyone. I'm study recommendation engines, and I went through the paper that defines how Google News generates recommendations to users for news items which might be of their interest, based on collaborative filtering. One interesting technique that they mention is Minhashing. I went through what it does, but I'm pretty sure that w...

Generating the permutations from a number of Characters

I'm working on a predictive text solution and have all the words being retrieved from a Trie based on input for a certain string of characters, i.e. "at" will give all words formed with "at" as a prefix. The problem that I have now, is that we are also supposed to return all other possibilities from pressing these 2 buttons, Button 2 and...

Permutations with extra restrictions

I have a set of items, for example: {1,1,1,2,2,3,3,3}, and a restricting set of sets, for example {{3},{1,2},{1,2,3},{1,2,3},{1,2,3},{1,2,3},{2,3},{2,3}. I am looking for permutations of items, but the first element must be 3, and the second must be 1 or 2, etc. One such permutation that fits is: {3,1,1,1,2,2,3} Is there an algorithm ...

Permutation algorithm without recursion? Java

Hi, I would like to get all combination of a number without any repetation. Like 0.1.2, 0.2.1, 1.2.0, 1.0.2, 2.0.1, 2.1.0. I tried to find an easy scheme but couldn't find so I drawed a graph/tree for it and this screams to use recursion. But I would like to do it without, if this is possible. So could anyone please help me how to do th...

Trying all permutations

For my program, I am trying to assist the user, and reduce his or her work load. There are four input numbers. There is also an indeterminate amount of numbers they can be applied too. For example, they four input numbers could be {4,7,3,2} and the numbers they can be applied to are {4,9,23} The result should be: 4 (input) was applied...

Permutation algorithm in the form of..

R= repeats allowed -> 2 A= alphabet (1-10) S= space = 4; So we want example: [1][1][4][5] [1][7][4][5] [5][1][4][5] But need a fancy math formula to calculate this and all combinations ? ...

Generating All Permutations of Character Combinations when # of arrays and length of each array are unknown

Hi everyone, I'm not sure how to ask my question in a succinct way, so I'll start with examples and expand from there. I am working with VBA, but I think this problem is non language specific and would only require a bright mind that can provide a pseudo code framework. Thanks in advance for the help! Example: I have 3 Character Arrays ...

All possible permutations of a set of lists in Python

In Python I have a list of n lists, each with a variable number of elements. How can I create a single list containing all the possible permutations: For example [ [ a, b, c], [d], [e, f] ] I want [ [a, d, e] , [a, d, f], [b, d, e], [b, d, f], [c, d, e], [c, d, f] ] Note I don't know n in advance. I thought itertools.product wou...

Is there an R function to get the number of permutations of n objects take k P(n,k)?

..or do I have to give P.nk <- factorial(n) / factorial(n-k) or P.nk <- choose(n,k) * factorial(k) Thank you. ...

Correct permutation cycle for Verhoeff algorithm

Hello, I'm implementing the Verhoeff algorithm for a check digit scheme, but there seems to be some disagreement in web sources as to which permutation cycle should form the basis of the permutation table. Wikipedia uses: (36)(01589427) while apparently, Numerical Recipies uses a different cycle and this book uses: (0)(14)(23)(56789),...