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Questions tagged [permutations]

A permutation is a particular ordering of some list of objects. Problems tagged with permutation usually involve finding or generating permutations, including anagrams of text.

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Hide the buildings

Shorter version of Skyscrapers Challenge Task Given an array of building heights and a positive integer k, find all the permutations(without duplicates) of the ...
-2
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3answers
119 views

Doce logf a string swapper [closed]

Challenge Take an input string \$s\$, and split it into words \$w_1, w_2, ..., w_n\$. If the amount of words is odd, then return \$s\$. Otherwise, for each word: Take the second last letter, and swap ...
7
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5answers
362 views

9erilous 9ermutations

Note: This is an attempt at recycling guest271314's permutation question(s) There's an interesting pattern that forms when you find the differences between lexographically sorted permutations of base ...
10
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5answers
293 views

Amidakuji (阿弥陀籤) simplification

If you have ever had any exposure to Japanese or East Asian culture you will have surely encountered the Amidakuji game: As Wikipedia explains, it is a type of lottery drawn on paper and used to ...
23
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23answers
3k views

Encode - Shuffle - Decode

Challenge Your task is to encode an integer as a string of ASCII characters, then successfully decode it after said string has been randomly shuffled. You will write two programs/functions, which ...
5
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0answers
264 views

What is the simplest reversible circuit that computes conjugacy of transpositions?

Reversible computation refers to computation in which little or no information is deleted. Reversible computation a major component of quantum computation, and reversible computation is potentially ...
7
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4answers
403 views

Permutation Encoding

Write a program which can encode text to avoid reusing characters, and convert back. Both normal and encoded forms are restricted to a particular character set: the space character ...
14
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9answers
1k views

Block Rearrangement

So your task is to take a 3x3 block where -'s mean blank spaces, and *'s mean filled spaces, for example: ...
28
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21answers
3k views

Levi-Civita symbol

The three-dimensional Levi-Civita symbol is a function f taking triples of numbers (i,j,k) each in ...
22
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13answers
2k views

Codegolf the Hafnian

The challenge is to write codegolf for the Hafnian of a matrix. The Hafnian of an 2n-by-2n symmetric matrix ...
17
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8answers
772 views

Conjugate permutations

A permutation of size n is a reordering of the first n positive integers. (meaning each integer appears once and exactly once). Permutations can be treated like functions that change the order of a ...
14
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12answers
1k views

Stitch Together a Palindrome from Palindromic Substrings

Given a string l, find all palindromic substrings p of l (including duplicates and single ...
14
votes
8answers
435 views

Deranged Rearrangements

Your task is to write a computer program such that when it is cut up into lines (split on the newline character) every arrangement of the lines will output a different number between 1 and n! (where n ...
8
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4answers
173 views

Flattened Spiral Permutation Index

Context Consider square matrices with n columns and rows containing the first n^2 (i.e. n ...
9
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2answers
481 views

How many draws are there in Quarto?

Introduction This challenge is similar to Project Euler problems. I came up with it because I was playing a deceivingly simple board game and couldn't come up with an efficient solution to answer a ...
23
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26answers
2k views

Find The Rank Of A Word

Definition The rank of a word is defined as the position of the word when all the possible permutations (or arrangements) of its letters are arranged alphabetically, like in a dictionary, no matter ...
12
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12answers
1k views

Generate combinations that add up to a target value

Challenge Suppose you have a list of numbers, and a target value. Find the set of all combinations of your numbers which add up to the target value, returning them as list indices. Input and Output ...
21
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3answers
740 views

​L​o​o​p​ ​I​t​

Note: The title of this question should be "Loop It", but because title needs to be at least 15 characters, there are some invisible spaces. This note is such that the challenge can be searched for. ...
19
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5answers
560 views

A Dance of Many Dimensions

Challenge Given a n-dimensional array of integers and a permutation of the first n natural numbers, permute the array ...
6
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5answers
214 views

Riffle shuffle a string - Robbers

Cops post A riffle shuffle is a way of shuffling cards where the deck is split into 2 roughly equal sections and the sections are riffled into each other in small groups. This is how to riffle ...
8
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9answers
408 views

Riffle shuffle a string - Cops

Robbers post A riffle shuffle is a way of shuffling cards where the deck is split into 2 roughly equal sections and the sections are riffled into each other in small groups. This is how to riffle ...
2
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4answers
126 views

String Permutations - case and order [duplicate]

Challenge For any string that is composed of alphabetical characters of any case, make a function that returns a list of all of it's variations, order and case-wise empty strings returns empty list. ...
14
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11answers
555 views

N-bit Variation on Subset-Sum

For another challenge I am writing, I need to verify that test cases are solveable with bounded integers. Specifically, I need to verify the following, for a non-empty array of integers ...
21
votes
8answers
1k views

Build this pyramid

Your pyramid The pyramid I want you to build is made entirely of cubes. It has 24 layers, and the Nth layer from the top contains N2 cubes arranged in an N by N square. The pyramid looks like this: ...
27
votes
29answers
5k views

Output an Anagram! No Not That One!

Given a list of unique strings that are anagrams of each other, output an anagram of those words that is different from each word in the list. The strings will be alphanumeric, and there is ...
9
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6answers
559 views

Output all distinct permutations of a vector

Challenge: Output all distinct permutations of a, potentially long, list of positive integers. You may assume that the vector has less than 1,000 numbers when testing, but the process should in ...
4
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0answers
193 views

Those annoying grasshoppers [closed]

The problem #6 of IMO 2009 reads: Let a 1, a 2, a 3, ..., a n, be distinct positive integers and let T be a set of n-1positive integers not containing a 1+a 2+a 3+...+a n, A grasshopper is to ...
17
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10answers
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Numbers with similar powers

Given an integer p > 1, find the smallest integer q > p such that the list of exponents in the prime factorization of q is the same of that of p, no matter the order or the value of the prime factors. ...
18
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12answers
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The Original Number (II)

This challenge is essentially identical to this one with just one difference: it is now allowed to shuffle letters anywhere in the string. Scenario John has an important number, and he doesn't want ...
22
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36answers
4k views

Reliably Broken Sort

Given a list of positive integers that contains at least 3 distinct entries, output a permutation of that list that isn't sorted in ascending or descending order. Examples ...
27
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5answers
545 views

Bubble the brackets!

There are a few questions on this site about balancing brackets, and checking whether brackets are balanced. I propose it's now time to use those balanced brackets for something! In mathematics and ...
9
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11answers
336 views

Construct a Permuter

For this challenge you are going to make a function (your function may be a complete program) that takes a list as input and returns a permutation of that list. Your function must obey the following ...
22
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12answers
3k views

Color me a Pole

Lets say your job is to paint poles, and a client asks you to paint a pole with 4 red sections and 3 yellow sections. You can do that pretty easily as follows: ...
36
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21answers
3k views

The Original Number

Guidelines Scenario John has an important number, and he doesn't want others to see it. He decided to encrypt the number, using the following steps: His number is always a non-decreasing sequence (...
19
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14answers
4k views

Counting from 1 to n without any consecutive numbers

Goal You are given an integer n (n > 1). You must output how many permutations of the integers ...
11
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5answers
476 views

Smallest unused number sharing a factor

This is a pretty run of the mill question. I will define a sequence and you golf some code to output a entry given a index. The first item in the sequence is 2. The nth item in the sequence is the ...
8
votes
3answers
505 views

Solve an Anagram

See also: Granma loves Ana You will be given a string of lowercase ASCII letters. Using this dictionary file (UPDATED), your task is to solve the anagram. To solve an anagram, you must output all ...
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8answers
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Find all the Anagrams, and the Subanagrams too!

This question is heavily based off this question, but should pose a number of additional difficulties. Your Task You must write a program or function that, when receiving a string, prints out all ...
16
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16answers
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Find all the Anagrams!

Despite having 17 questions tagged anagrams, we still don't have this question, so here it is. Your Task You must write a program or function that, when receiving a string, prints out all possible ...
2
votes
0answers
96 views

Is that string garbled? [duplicate]

Mayube recently posted Garble that string. However, humans aren't too good at checking whether a string is actually garbled or not. (Actually, that's an understatement, we are really bad at it.) So, ...
20
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9answers
967 views

Garble that string!

Given a string as input, output one or more variants of the string such that: No character is in it's original position No character is adjacent to a character that it was originally adjacent to You ...
23
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38answers
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Golf an Anagram Quine

In this question I asked you to guess an anagram quine based on its output. However it looks like we don't have a question asking to golf an anagram quine yet. So your task will be to make the ...
16
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10answers
1k views

THE Magic Hexagon

There are many magic squares, but there is just one non-trivial magic hexagon, as Dr. James Grime explained, which is the following: ...
41
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11answers
4k views

Find a binary needle in a decimal haystack

The challenge You're given: a non-empty, unsorted list h of positive integers (the haystack) a positive integer n (the needle) Your task is to return the list of all unique decimal concatenations ...
12
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7answers
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Golf you an anagram for great good!

The Task In this challenge, your task is to write some code which outputs one of its anagrams chosen randomly with uniform distribution but it should never output itself. Elaboration Given no input,...
8
votes
6answers
915 views

It's Anagram Quine, not just Quine!

The Task In this challenge, your task is to write a program, which takes in no input, with as many anagrams that are quine of themselves as possible. Your score will be the number of anagrams of ...
23
votes
16answers
1k views

Random Golf of the Day #8: Shuffle an infinite list

About the Series First off, you may treat this like any other code golf challenge, and answer it without worrying about the series at all. However, there is a leaderboard across all challenges. You ...
44
votes
12answers
2k views

Scramble words while preserving their outlines

This is much more advanced than How to randomize letters in a word and Cambridge Transposition because of the rule about which letters may be swapped with which. A simple regex will not suffice here. ...
19
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6answers
1k views

Anaglot Polygrams

Task Write some code that can be rearranged into n different programs in n different languages each outputting a distinct number from 1 to n. No two languages should be the same however different ...
14
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5answers
382 views

Generate all Brain-Flak Snippets

This question is the second of several Brain-flak Birthday challenges designed to celebrate Brain-Flak's first Birthday! You can find more information about Brain-Flak's Birthday here Challenge For ...