# Questions tagged [sorting]

This challenge is intended to be solved by sorting, ordering, or otherwise organizing some set of data.

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### Interviewer's Room

You are James and four of your friends (Bjarne, Eich, Rossum, Ada) are called for an interview. There are n interviewers, and they can each serve one person at a time, alphabetically. Each round of ...
254 views

### Too much lines for me! [closed]

The problem You just got a new job, hurray! You expect to be given various interesting tasks, and be able to learn a lot in the next few months. Good news, your boss gave you your first work this ...
5k views

### Help, I've mixed my week up!

My dog ate my calendar, and now my days are all mixed up. I tried putting it back together, but I keep mixing up the days of the week! I need some help putting my calendar back together, with the days ...
2k views

### Pendulum Encoding

Given a string as an input (which can be any acceptable/convenient format in your language), implement pendulum encoding. The test cases are split into individual items (which aren't quoted) for a ...
373 views

### Swaps to Sort an Array

You are given an array $A$, which may contain duplicate elements. In each swap, you may swap the value of any two indices $i, j$ (i.e. switch the values of $A_i$ and $A_j$). What is the least ...
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### Integer Interpretator

The Challenge Given a finite list of integers, split it into the fewest partitions possible such that no partition contains a number more than once. Rules Input can be in any format and any order. ...
203 views

### Two stack sorting

This challenge is inspired by the same task I read some time ago in CACM. There are many ways to sort stuff. Most attempt to sort in as few operations as possible (= as fast as possible). However, it ...
3k views

### Roll for Initiative!

Roll for Initiative! Introduction In tabletop games like Dungeons and Dragons, when you begin a battle, all involved parties roll for initiative. In DnD 5e, this is ...
2k views

### Sort and Table a Sentence by Word Lengths

In as few bytes as possible, sort the input, a delimited string OR list/vector/array of words, words contain printable ASCII except space (ASCII values 33-126) into a numbered list, table, or ...
422 views

### North Korean dictionary order

The objective Given a string of Hangul syllables, sort the characters in North Korean dictionary order. Introduction to Hangul syllables Hangul(ķźø) is the Korean writing system invented by Sejong ...
218 views

### Dropsort with a Twist

This is my first attempt at a Code Golf question. If it needs obvious edits, please feel free to make them. Below is a description of the basic Dropsort algorithm. Dropsort is run on a list of ...
3k views

### A quine of sorts

Given a string x, output the characters in x sorted according to the order of appearance in your source code. Examples ...
395 views

### Write the shortest O(n^2) sorting algorithm [closed]

Write a sorting algorithm for a list of integers that has an average performance of O(n^2). This is code-golf, so the shortest code in bytes wins. RULES: The characters wasted for the declaration of ...
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### Rotated Position of Integers

Challenge: Input: A sorted list of positive integers. Output: The amount of integers which are still at the exact same index, after rotating the digits in each integer its index amount of times ...
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### Arrow those variables!

Challenge Robin likes having his variables declaration in the shape of an arrow. Here's how he does it: Input any number of strings Order them by ascending length Output them ordered by the middle ...
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### Implement the Thanos sorting algorithm

The sorting algorithm goes like this: While the list is not sorted, snap half of all items (remove them from the list). Continue until the list is sorted or only one item remains (which is sorted by ...
440 views

### Matrix rotation sort

Lets define a non-empty, unsorted and finite matrix with unique numbers as follow: $$N = \begin{Bmatrix} 4&5&7\\1&3&6 \end{Bmatrix}$$ Lets define 4 matrix moves as: ā* (up): Moves a ...
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### Enumerate each series of identical numbers in-place

Given a list of strictly positive integers, go through each distinct number and replace all occurrences of it with successive indices (zero or one based) of a new series. Examples ...
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### Sort by Largest Digit(s)

Challenge: Given a list of integer, sort descending by their single largest digit(s). The order for numbers with the same largest digit are then sorted by second largest digit, etc. We ignore ...
5k views

### A “Sorting” algorithm

There is a "sorting algorithm" sometimes called Stalin sort in which in order to sort a list you simply remove elements from the list until it is sorted in increasing order. For example the list <...
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### Blind Random Sort

Here's a pretty common pattern for sorting algorithms: ...
5k views

### PronunciationSortā¢

We all know of different fancy sorting algorithms, but none of these give us numbers in a way that's easy to pronounce. To remedy this, I propose using PronunciationSortā¢, the most natural way to sort ...
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### Rubik-sorting a matrix (a.k.a. the torus puzzle)

The idea for this code-challenge is simple: given a matrix of integers, let's sort it by applying Rubik-style movements. This means that you can select a single row or column and rotate its elements ...
2k views

### Block-sorting rows and columns in a 2D array

Given a 2D array of integers, let's sort its rows and columns in blocks. This means that you only have to sort a given row or column, but applying the transformations needed for sorting it to every ...
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### Indentation-based Sort

Given an ordered list of same-case letter strings (a-z XOR A-Z) where each string is preceded by 0 or more space ( ) characters, output the same list but with the strings sorted at each level of ...
2k views

### Sort by what the digit pairs describe

Given a positive integer, we can form a new number that's described by its digits taken pairwise (with a leading 0 added for numbers with odd number of digits). For eg.: 1234 can be read as one 2, ...
503 views

### Codegolf Rainbow : Sorting Colors with Reflection

Introduction: After I posted two rainbow-related challenges: Codegolf Rainbow : Fun with Integer-Arrays 1 and Codegolf Rainbow : Draw in Black-and-White 2, the following comment was made by @ChrisM in ...
983 views

### Let's practice the scoring rules of 421!

421 is a rather popular dice game in France and some other European countries. It is mostly played in bars and pubs to determine who's going to buy the next round of drinks. The full game is usually ...
473 views

### Einstein's Sorter

Challenge Given a list of integers and a velocity, $v$, implement a sorting algorithm which simulates a program sorting the list from smallest to biggest at the given velocity. Einstein's Theory ...
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### Sort of numbers

Within the recesses of Unicode characters, there exists a Unicode block of (currently) 63 characters named "Number Forms", which consists of characters that have numerical values such as the roman ...
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### Sort odd numbers first

Rearrange a given list such that all the odd numbers appear before all the even numbers. Besides for this requirement, the output list may be in any order. The input will only contain integers, but ...
335 views

### Pair and sort from two integer lists

You are given two arbitrary integer lists, e.g. [-10, 99, -6, 43], [100, 32, 44]. You are to pick one integer from each list and ...
422 views

### Implement Tyrant Sort [closed]

TL;DR Record (left-right)/length for each pair of consecutive elements. If they're 0 or negative, don't record it. Once this is done, take these actions. Don't update quotients: Increment right and ...
123 views

### Sorting Algorithms for Physical Process [closed]

Not sure if this is the correct community to post this is. But as I see this problem as an interesting puzzle to solve, I'd thought to give it a shot... Problem Statement: Let`s say we have: N ...
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### Sort spelled-out serial numbers

Given a list of two or more spelled-out serial numbers of equal length greater than two, e.g. ...
4k views

### Implement Lazy Drop Sort

This challenge already describes dropsort. However, I'm kinda lazy and I really only need my array to be a bit more sorted than before, it doesn't need to be sorted all the way. In Drop Sort, we drop ...
429 views

### Help John watch movies!

Introduction So John finally has his holidays! And what better could he do than watching some movies. He indeed has a lot of movies to watch, but he is unable to decide which one to watch first. He ...
648 views

### Sort by shuffling blocks

Block shuffle sort The block shuffle sort is a (rather artificial) method of sorting a list. It works as follows, illustrated by an example. ...
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### There are two new sheriffs in town ā Identifying DJMcMego pairs!

We have some new sheriffs moderators in town, Mego and DJMcMayhem. We need a challenge to properly honour them for their new positions, so there we go. Here's something that has caught my attention ...
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### Minimally sort a list into a matrix

Given an unsorted list of unique strictly positive integers, minimally sort it into a 2D matrix. The input list is guaranteed to be of composite length, which means the output matrix is not ...
675 views

### Can you outgolf Bill Gates?

Pancake sorting is the colloquial term for the mathematical problem of sorting a disordered stack of pancakes in order of size when a spatula can be inserted at any point in the stack and used to flip ...
314 views

### Sorting for search by monotomy

Statement Given N distinct integers, output them in order such that for any integer J from 2 to N, for any K>0 obtainable by dividing J by 2 (rounding down) at least one time, the Jth integer ...
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### Tell me how to flop

As computer scientists, you're probably all familiar with the basic list operations of pop and push. These are simple operations that modify a list of elements. However, have you ever heard of the ...
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### 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 if ...
2k views

### XOR sort an array

Given a key, and an array of strings, shuffle the array so that it is sorted when each element is XOR'd with the key. XOR'ing two strings To XOR a string by a key, XOR each of the character values ...
189 views

Christmas is coming up, and this year you have been charged with organizing your family's christmas get-together. You have a list of foods you want be there, but before you assign foods to people, you ...
8k views

### Find the longest word in an array

Your challenge is to take an array of strings and output the longest string in the array. So for ["tiny", "small", "bigger", "biggest"] the output would be ...
2k views

### Visualize Merge Sort

Merge sort is a sorting algorithm which works by splitting a given list in half, recursively sorting both smaller lists, and merging them back together to one sorted list. The base case of the ...