# Questions tagged [array]

An array is an ordered data structure consisting of a collection of elements (values or variables), each identified by one (single dimensional array, or vector) or multiple indexes.

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### Snake game using PyGame

I wrote a simple Python snake game which is about 250 lines of code. Can someone give me some advice on how I can refactor/make it better? game.py ...
10k views

### How can I quickly find unique list items?

I use the loop-every-single-list-item approach to filter out unique elements in a given list, which tends to be very inefficient way as a list grow in size, or as function call frequency increases. ...
2k views

### Finding the sub-array with the maximum sum - my approach

This is the code I ended up with that implements the approach I described in a recent answer to another question about the same problem The basic idea here is to not loop through more things than ...
339 views

### Calculating the number of rooms in a 2D house

I stumbled upon this problem on cses.fi (a problem set for the Finnish Olympiad in Informatics. This problem is in finnish so I'll translate it). I'll describe the problem, present the code and think ...
500 views

### Creating an array that loops out on the frontend - Don't Repeat Yourself?

Entire Code Here Don't repeat yourself I know of the "Don't repeat yourself". Still it's getting messy in some places. The code below contains three blocks of code. They are similar in some ways ...
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### Finding words of different lengths given six letters

I'm trying to find all the 3, 4, 5, and 6 letter words given 6 letters. I am finding them by comparing every combination of the 6 letters to an ArrayList of words ...
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### Finding the first duplicate in an array

My code returns the correct answer the first duplicate is 3 (represented as int f) . I am struggling finding a more efficient way to find the first duplicate? My ...
180 views

### Associating degrees with notes of scales

I have a JS file that creates an object with notes from a music scale when given a key (aka tonic/ note). The code works and does what I want it to do. I need a critique on the way it's written, what ...
168 views

### Codility's Permutation Check in C#

I've made a few things in Java, and now I'm learning C#. The code passes the tests with 100% final score. I want to know what things can be improved in my code. Task description A non-empty ...
997 views

### Python ASCII-Art Table

As a part of a console utilities module, I created a function that takes a table in the form of an array of arrays, and generates an ASCII table with the given contents. I've also added the options ...
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### Find the missing number in a array

I'm working on a personal project to practice my programming skills and I came to this problem. I tried to create a program that will find the missing number in a array. I'm looking forward to ...
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### Split the array so that the sum of the numbers on one side of the split equals the sum of the numbers on the other side

I would really appreciate if you can help me to find a better way to do it. ...
166 views

### Find sum of number of times that each character of source occurs in the target

I wrote the following code in response to this question "find sum of number of times that each character of source occurs in the target", is there any better solution for it? Analysis ...
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### (Re)Creating a tree from a flat collection (or “unflatten” a tree)

I need to create a tree from a flat collection. The order of elements is defined in a specification so it's rather impossible that it will ever change... but I want the whole algorithm to be ...
620 views

### Finding number of number pairs with given difference [closed]

pairs() is a function which returns the total number of combinations whose difference is k. ...
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### Codility Cyclic rotation in C#

I'm learning C#, I programmed some things in java, and I would like to have a feedback on my C# code. The exercise is from codility. The goal is to rotate array ...
27k views

### Searching an element in a sorted array

I was applying for a position, and they asked me to complete a coding problem for them. I did so and submitted it, but I later found out I was rejected from the position. Anyways, I have an eclectic ...
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### Reverse a String in Java

Here is the code for the CString class that I created. ...
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### Find all the missing number(s)

Recently I've attended an interview, where I faced the below question: Question: "There is an sorted array. You need to find all the missing numbers. Write the complete code, without using any ...
20k views

### Index into array as if it is circular

The problem: Treat an array as if it is circular; out-of-bounds indices "wrap around" the array to become in-bounds. Current solution: ...
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### Duplicate like a weapon, arrays like heaven

Challenge: Find the duplicated entry. Specifications: Your program should accept as its first argument a path to a filename. Each line in this file is one test case. Each line begins ...
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### Calculate min, max, mean and median out of array

Another C exercise: Write a function that takes an array of 'ints' as its input and finds the smallest and largest elements. It should also compute the median and mean. Use a ...
133k views

### Modifying an array during a foreach loop [closed]

This question is always on my mind. I usually alter the array while looping through its keys, based on my gut feelings: ...
18k views

### Reverse words in a given String

I'd like this code to be improved Input string: codereview is awesome Output string: awesome is codereview My approach: ...
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### Flatten an array of integers in Python

The goal is to flatten an array of nested arrays of integers. For example [1, [2], [3, [4]]] should return [1, 2, 3, 4] I'm ...
589 views

### FiniteArrayQueue type with interface and unit tests

Doing some exercises on basic data structures, I learned about queues, and decided to roll my own to better understand how a basic queue can function. As the name indicates, this Queue is made from a ...
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### Implement numbering scheme like A,B,C… AA,AB,… AAA…, similar to converting a number to radix26

I want to implement numbering scheme like Microsoft Word uses for numbering. first one gets = A,next is B, next is C, .... then AA, then AB,....and so on. as shown below ...
34k views

### Implementing an ArrayList

I implemented ArrayList functionality in C as follows: ...
15k views

### Find the subarray with the max sum

In an interview I was asked to solve the following problem: find a subarray with max sum I have written a piece of code for the same. I need your help in reviewing this code. ...
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### Reversing the lines of a file

I am trying to reverse the lines of a file by reading the file through an array. Is there a more efficient and quicker way of achieving this? ...
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### Simple multi-dimensional Array class in C++11

The new version of the code can be reviewed in Simple multi-dimensional Array class in C++11 - follow-up. The following code implements a simple multi-dimensional array class (...
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### Optimizing unboxed array operations in Haskell

Consider this simplified code which successively permutes array elements: ...
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### Review implementation of stack by using array in C [closed]

This question has become long after many updates. Click here to go down. I have implemented stack using arrays in C. Please give me suggestions on how to improve it. The purpose of writing it is ...
27k views

### Given an array of integers, return all pairs that add up to 100

I was recently given this programming challenge on an interview, and I decided to use javascript to solve it. I did, but I'm not happy with my implementation. I can't help thinking there must be a ...
229 views

### Array-like container for uints shorter than 8 bits

Follow-up: Array-like container for uints shorter than 8 bits (Rev 1) First of all: yes, I need this kind of array to generate data for a piece of hardware, and it must be stored and manipulated ...
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### Multi-dimensional container using operator[]

This is a late followup to a previous question of mine on same subject. Context: I want to have a tool that allows to use all the C++ goodies (algorithms, for loop on containers, etc.) on a ...
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### Checking if an array is sorted

I've come up with two ways to check to see if array is sorted and return true if it is. ...
323 views

### Simplified implementation of std::vector in C++

I implemented a simplified version of a C++ std::vector/ArrayList learning from this link. From it, I tried to write an ...
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### DoublingQueue in Java

Inspired by this CR question, I decided to create my own queue! If you guys see anything taboo or have any improvements, please let me know. Ultimately I want it to be feature rich and bug free, with ...
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### Find median of two sorted arrays

Problem statement There are two sorted arrays nums1 and nums2 of size m and ...
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### Optimise compare and match method using scripting.dictionary in VBA

In my previous post I was looking for a better solution to write a single column of a 2D array into a worksheet besides looping between code and worksheet and finally managed to achieve that. On ...
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### Simple multi-dimensional Array class in C++11 - follow-up

Last week, I posted this question in order to get some comments and critiques on a simple implementation of a multidimensional array class -- hyper_array::array ...
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### Using 2D arrays to make more efficient sequential storage

This code is part of a growing "primitive" tools collection here on github Use Case Consider: ...
226 views

### Earliest time frog can jump to the other side of a river in C#. Codility's task

I'm new to C#, I programmed a little in java in the past.I had the two previous exercises reviewed here (permCheck, cyclicRotation, with a 100% score, just like this one), and I'm applying what the ...
370 views

### Array-like container for uints shorter than 8 bits (Rev 1)

This is a follow-up to Array-like container for uints shorter than 8 bits In short: The PackedBitfieldArray should be a kind of container for packed (unsigned) ...
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### Binary search for inserting in array

I have written a method that uses binary search to insert a value into an array. It is working, but i would like to get a second opinion to see if i didn't write too much code for it. aka doing same ...
21k views

### Method to convert String to int array

I was working on a suggestion for this question, but the method, I would've suggested the OP do something similar to, seems a bit convoluted. It's supposed to take a String input and return an array ...
In preparing this answer, one of the components was an algorithm to rearrange a sorted array in a particular way. To put it succinctly, here's the problem description: Given an array $A$ with \\$...