Questions tagged [array]

A competition to solve a particular problem through the usage and manipulation of arrays.

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Shorter than a Split Second!

Challenge You task for this question is to split an input array of integers on the second occurrence of every integer in that array. Not clear enough ? Here is an example to help Input array: ...
3k views

Create an array with repeated numbers

Challenge Your task in this question is to write a program or a named function which takes a positive integer n (greater than 0) as input via STDIN, ARGV or ...
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Mode (most common element) of a list

Write a snippet to calculate the mode (most common number) of a list of positive integers. For example, the mode of d = [4,3,1,0,6,1,6,4,4,0,3,1,7,7,3,4,1,1,2,8] ...
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Shortest Code to Translate a PHP array

NOTE: This question was migrated from https://stackoverflow.com/q/27134588/1442685 PHP QUESTION Almost purely out of curiousity, how can I take an array like this: ...
712 views

Shortest program to split special array

Background Imagine, you have a big array A, which is mostly zeroes, but contains a short subarray B which has only strictly ...
1k views

Book Stack Sort

When stacking books you usually want to put the largest ones at the bottom and the smallest ones at the top. However, my latent OCD makes me feel very uneasy if I've got two books where one is shorter ...
107 views

Approximated (unsorted) square from a set of values [closed]

So a colleaque came with this problem lately and I want to challange you to solve the problem in the code-golf style, shortest solution in any language wins. The Problem: Given is a random set of ...
231 views

Create an array of unique ints in a set range [closed]

Goal: Write a piece of code that produces a array containing all integer values in a set range in random order (upper and lower bounds included). Use any language you like, but use as little built-in ...
476 views

Golfscript Diagonal Array

Is there a way in Golfscript to bring all of the diagonals of an array into a single array? For example, for the array [[1 2 3][4 5 6][7 8 9]] return ...
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Generating a single string with an Oxford comma from a list

What are some clever (brief and idiomatic) approaches to taking a list of strings and returning a single properly punctuated string built from the list, with each element quoted. This came up for me ...
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Programming Praxis - Survive like Flavius Josephus [duplicate]

Here's a challenge inspired by Programming Praxis: http://programmingpraxis.com/2009/02/19/flavius-josephus/ Write a function josephus(n,m) that returns a list of n people, numbered from 0 to n-1, in ...
947 views

Rank a list of scores with "skips"

Given a list of scores (non-negative integers) pre-sorted from greatest to least: [ 10, 10, 6, 6, 4, 0] Assign each score an integer rank, beginning with 1 ...
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Rotate 2D Array [duplicate]

Given an input of a 2 dimensional array of integers, rotate the array 90 degrees clockwise. It should work for rectangular arrays of all sizes and proportions. The rotated array should be printed at ...
759 views

Deplane! Deplane! (Or: RGBRGBRGB => RRRGGGBBB?)

Imagine bytes in memory for an RGB image--R and G and B represented by bytes in sequence. If an image is NxM then the memory layout will be M repetitions for vertical scanlines of 3*N bytes in ...
989 views

Stack the deck!

Alice and Bob like to play a card game, with a deck of cards numbered with consecutive nonnegative integers. Alice has a very particular way of shuffling the deck, though. First, she takes the top ...
364 views

Remove Duplicates From One List [duplicate]

Task: Remove all duplicates from one list of integers. A list is simply a sequence of connected values that allows the same values to be stored at different positions in this sequence. If an item ...
571 views

Generate lists in which every sublist has a unique element

The problem is defined as follows: Create a function that takes an integer and returns a list of integers, with the following properties: Given a positive integer input, n, it produces a list ...
5k views

Terms A worm is any list of nonnegative integers, and its rightmost (i.e., last) element is called the head. If the head is not 0, the worm has an active segment consisting of the longest contiguous ...
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Shortest C \ C++ function to generate -1, 0 ,1 [closed]

Let a function receive two integers i and j between 0 and ...
10k views

Rotate An Integer Array with an O(n) algorithm [closed]

Write a function that rotates an integer array by a given number k. k elements from the end should move to the beginning of array, and all other elements should move to right to make the space. The ...
472 views

How many times is rectangular array A embedded in rectangular array B?

Given two rectangular arrays, A and B, let's say that A is embedded in B if A can be obtained from B by deleting some (or none) of the rows and columns of B. Write a program with the following I/O: ...
688 views

Change the innermost element type of a jagged array — any .NET language: C#, F#, VB.NET, MSIL, C++/CLI, etc

Write a class containing a method with the signature System.Array ChangeElementType(System.Array jaggedArray) (you may rename identifiers ...
991 views

Avoid duplicate entries using a sign change

This anecdote contains the following intriguing exchange: "Fine, Fred," Avi interrupted. "Then how would you change this to avoid duplicate entries?" "Oh, just change that one there to a ...
6k views

Convert JSON string to Key / Value Arrays

Convert JSON (key/value pairs) to two native arrays, one array of keys and another of values, in your language. ...
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Javascript: Create a 10x10 array of 1s

Obviously this challenge would be trivial with separate functions and libraries, so they aren't allowed. Your code must conform to an ECMAscript specification (any spec will do), so no browser-...
342 views

Merge working time periods

You have an array of working time period pairs (from, till) received from user input and written according 24-hour clock format convention. You have to merge these periods if the intersect each ...
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Shortest power set implementation

Problem definition Print out the powerset of a given set. For example: [1, 2, 3] => [[], , , , [1, 2], [1, 3], [2, 3], [1, 2, 3]] Each element is to ...
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Array Sandwiches

(Adapted from Problem C of the first qualifier of the ACM Programming Contest of 2012/2013) You have several arrays, named $A_1, A_2, ... , A_n$, each sorted in ascending order. Every item in the ...
580 views

Create a hash from an array of arrays of key|value pairs [closed]

Starting from an array of sub-arrays, each sub-array is a 2 elements key|value pair. Example input = [["A", 5], ["B", 2], ["A", 12], ["B", -2], ["C", 7]] Convert ...
802 views

Finding duplicate balls in a basket? [closed]

A basket is full with $n$ colored balls. For each color except one, there are at least 2 balls with that color. Find the color which only has one ball. in $O(n)$ space complexity. What if each ...
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Operations with Lists

Inspired by this question. Given a list containing numbers, print: The sum and product of the numbers in the list The average and median The differences between each term in the list (e.g. ...
206 views

Reduce the amount of loops when finding if an element is stored only once in the array? [closed]

I was amazed to find that there is a way to reduce the times you loop on an array to find if a element is contained once. One would think that the only way would be to loop through the whole array, ...
588 views

Polynomial extrapolation

Task Given a list of integers a1, a2, …, ak (k ≥ 2) and a positive integer m, write a function or a complete program that calculates the next m numbers of the list. Assume that ai = P(i) where P(x) = ...
4k views

Shuffle a deck without local variables [closed]

The object of this puzzle is to take a deck of 52 cards and shuffle it so that each card is in a random position. Given: An array, deck, of 52 distinct integers ...
1k views

Numbers, Sums, Products

Given a 20×20 grid of non-negative integers, find a 3×3 sub-grid where the product of the sums of the individual lines hits the maximum. Spoken in formulas: Given the 3×3 sub-grid \mathfrak{U} = \...