Questions tagged [recursion]
Recursion in computer science is a method of problem solving where the solution to a problem depends on solutions to smaller instances of the same problem.
885
questions
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1answer
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Recursive Mergesort using goroutines
When learning a new language, one of my first tasks I like to go through is writing a few different sorting algorithms in that language to help familiarize myself with the syntax and see if there are ...
2
votes
1answer
46 views
recursive function improvement
I am creating routes from an array of menuItems. I have written a recursive function, which works fine but I think the code can be improved. So, I need you guys to review my code and suggest me some ...
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0answers
77 views
Recursion on graphs - networkx VS adjacency lists with native lists, sets or numpy vectors ( python )
Hope someone can help me out in reviewing this code to make it faster.
My goal is to create a graph recursively:
query for a node and its neighbors from a db (not present here)
add it and its ...
1
vote
1answer
49 views
Don't include root directory in HTML tree
I've written a function to create an HTML tree from JSON.
...
2
votes
1answer
46 views
interpre function implementation
Here is the description of the problem.
Write a simple interpreter which understands "+", "-", and "*" operations. Apply the operations in order using command/arg pairs starting with the initial ...
11
votes
5answers
3k views
Brute-Force algorithm in C++
I wrote a brute-force algorithm which shall find all possible combinations of ASCII-values that can sum up to a specific value (int hashval).
The algorithm is ...
0
votes
1answer
84 views
Fibonnaci sequence calculation [closed]
Below are two ways to calculate an element of the Fibonacci series. Can someone please help me understand why fib1 is so much faster (over 60x) than ...
2
votes
1answer
42 views
Recursively find files of certain types and log their paths (C++)
I've written a function that takes a list of extensions and recursively finds files of those types, and logs their paths to a text file.
Usage example (finding image files in a home directory):
<...
2
votes
0answers
25 views
File and folder filter for a “last-updated explorer”
Sometimes I save a file somewhere but can't find it after or I install something and want to see what files were added. For this reason, I created a winforms app which only displayes files created/...
4
votes
2answers
59 views
User defined function call on a stack based interpreter for concatenative language
I would like to receive some advice on how to improve a small concatenative stack-based interpreter, executing a joy-like programming language. It is really minimal, and is in fact a subset of a ...
1
vote
1answer
60 views
Tower of Hanoi, ASCII animation with ANSI escape codes
A few days ago I saw a nice video on YouTube with prof Thorsten Altenkirch about recursion and the Tower of Hanoi puzzle. Today I tried to reproduce the code from the video and came to this:
...
4
votes
2answers
109 views
Get list of all combinations from a set
Given a tuple of elements, in elementTupleParam and the number in each combination r, we compute all the possible combinations ...
7
votes
2answers
129 views
Letter Combinations of a phone number using a Dictionary
Problem statement (online source)
Given a digit string, return all possible letter combinations that the
number could represent.
A mapping of digit to letters (just like on the telephone ...
5
votes
2answers
330 views
Selection Sort Algorithm (Node.js)
I wanted to implement a selection sort and wanted to make sure that I'm doing it correctly. I wanted to do it in a way that's efficient and use recursion. Please let me know if I am doing this ...
11
votes
1answer
112 views
Recursive code to generate a parametric sweep of input values
I generate a set of data based off every combination of inputs. The source range that's inputs requires headers to identify the parameters. In its present state I'm not content as it's not as ...
4
votes
2answers
124 views
Build a flat List from a Tree structure in Java
I have a Tree structure represented by a List, which I want to get it flattened.
I wrote the function below:
...
3
votes
1answer
36 views
Batch rename files recursively, and number the directory index
When dealing with iOS app bundle, It is not convenient to get the file by its path, but loading it by its name.
Need to batch rename images recursively, with Mac Bash. And to make the name unique, ...
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vote
0answers
65 views
Recursion to dynamic programming [closed]
I was trying to solve a problem on de-arrangements (Number of partial derangement such that exactly prime number discs are found away from their natural positions? (Any number of non-prime K disks ...
5
votes
0answers
83 views
Mahjong hand completeness checking algorithm
As a summer project, I have been working on a small-scale, console-based version of Mahjong (the Rummy-like hand completion game, and not the solitaire version). While having prior knowledge of the ...
5
votes
1answer
125 views
Change tracking POCO entities
Description
In a time where thin clients, web browsers, web services and micro services are prevalent, we tend to forget we still have to deal with thick and smart clients. Many applications in B2B ...
5
votes
0answers
44 views
JS deep merging of objects- removing empty keys
I've written a helper for combining objects (deep merge).
It works, and is flexible to add options (like uniq and replace).
...
2
votes
0answers
34 views
Leetcode Finding Maximum Area of Island Solution
Given a non-empty 2D array grid of 0's and 1's, an island is a group
of 1's (representing land) connected 4-directionally (horizontal or
vertical.) You may assume all four edges of the grid are ...
2
votes
1answer
38 views
Convert Sorted Array to Height Balanced Binary Search Tree
Algorithm
This is my code to convert a sorted vector of integers to a balanced binary tree of the same content.
The binary tree is made of these nodes:
...
19
votes
3answers
4k views
Loading military units into ships optimally, using backtracking
I solved the following problem using backtracking:
We are given a list of military units, their weight and their
(numerical) strength. We have a number of ships with a limited
carrying capacity....
3
votes
2answers
64 views
Fixed Content Necklace Generator
I wrote a class that generates combinatorial necklaces with fixed content as per Sawada: A fast algorithm to generate necklaces with fixed content. The class is instantiated with an input list that ...
5
votes
2answers
154 views
Code Challenge: basic arithmic operations using only incrementation operator
Challenge
Write a function that takes 2 integer operands left and right
(both >= 0) and evaluates one of the following ...
7
votes
3answers
303 views
Sierpinski turtle triangle
I am working through Programming Fundamentals with Python on Udacity. The assignment was to create a recursive triangle. I am happy with the output, but I am hoping for feedback on the actual ...
4
votes
1answer
48 views
Find the total number of emails in a folder (with all of the subfolders)
The Folder struct definition below is given:
type Folder struct {
ID int
emailCount int
childFolderIDs []int
}
Description of the fields are:
...
2
votes
1answer
48 views
Traversing two trees until a common value has been found
I am traversing two objects that may share a common ancestor. To make the code small enough to show here, I have changed it into two dictionaries with values. As you can see, ...
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votes
2answers
1k views
Recursive search on Node Tree with Linq and Queue
This code is now maintained on GitHub
I've created a Node class which contains two important properties:
...
3
votes
1answer
113 views
Find A Series of Numbers Who when Squared and Summed are equal to a given Square
I am working on a CodeWars titled 'Square into Squares. Protect trees!' it can be found here: https://www.codewars.com/kata/54eb33e5bc1a25440d000891/train/javascript
I have a working solution, the ...
5
votes
0answers
188 views
Recursive conversion from ExpandoObject to Dictionary<string, object> #2
Because my original question was lacking many details, I have been advised to ask a new question.
I will repeat the important parts of the original question and add examples etc to hopefully make it ...
4
votes
4answers
839 views
Recursive conversion from ExpandoObject to Dictionary<string, object>
For my blazor library which is a modification of this awesome library I have to convert an ExpandoObject into a ...
1
vote
2answers
89 views
Combined looping and recursion when implementing Quicksort, using proper Clojure style
In "The Joy of Clojure", 2nd edition, code for quicksort is introduced on page 133 that I found hard to digest. I have rewritten it to make it clearer (at least to myself).
Here is the original:
<...
7
votes
3answers
535 views
Compiling all Exception messages into a string
Below is a recursive function I've written that's responsible for compiling a string consisting of a Exception's message, and also each of that ...
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votes
1answer
28 views
5
votes
2answers
490 views
Fetch and print all properties of an object graph as string
Below I have setup an extension method that takes any object, cycles through its properties, and prints each out to a Console window in the format Name: Value.
...
5
votes
1answer
288 views
A recursive Boggle solver
`Boggle is a word game in which letters are randomly placed in a 4x4 grid
e.g:
A D Q P
N L E M
O S R T
V K J H
Words can be started from any letter and are ...
8
votes
4answers
3k views
“What is the maximum that Player 1 can win?”
This is a question that I encountered in one of the competitive coding tests. The question goes as follows:
A 2-player game is being played. There is a single pile of stones. Every stone has an ...
9
votes
1answer
118 views
Tower of Hanoi with helper function
Here is my solution to the Tower of Hanoi problem using Python
...
4
votes
3answers
405 views
Generate parentheses solution
I have coded a solution to build all valid permutations of parentheses.
My code is below.
I have a question on my code based on a comment by my PEP8 checker. It said that there was no need to ...
2
votes
0answers
60 views
JSON flattening with object duplication on array property for CSV generation
I am looking for a way to transform JSON data into a flat "csv-like" data object. In some way, I am looking to "sqlirize" a mongodb collection. I have already check some json flat libraries in NPM ...
2
votes
2answers
93 views
Generating recursive class instances from an array of splitted values by dashes (as a folder tree)
Well, I'm trying to generate the following:
Input:
...
3
votes
1answer
2k views
Get all children recursively in Entity Framework Core
In Entity Framework Core we can have recursive entities. But we cannot do an "Include" for these recursives (can we?). So I wrote a Get-method that does it for me:
...
2
votes
1answer
119 views
Performing an action which may return other actions to be performed, concurrently
I have a program which, at its core, involves repeatedly performing an action on some value, and based on that action also returning a list of new values to perform that action on. The pure version of ...
3
votes
0answers
43 views
reverse recursive search on an object with javascript - like tree search
I implemented a tree search with JavaScript.
It has below basic rules.
It will search over an array of objects which has recursive(like fractal)
If it found a according data in a leaf(the final ...
1
vote
1answer
74 views
Python program to find the factorial of a number using recursion
A factorial of a number is the product of all the integers from 1 to that number.
For example, the factorial of 5 (denoted as <...
3
votes
1answer
258 views
Matryoshka Doll Recursion
I was tasked with writing a Matryoshka doll program that manages the following:
howManyDolls : returns an integer based on how many dolls are inside the stack
howManyWearingBabushkas : returns an ...
3
votes
1answer
70 views
Efficiency of a recursive implementation of the Sieve of Erasthotenes in Python
I implemented the Sieve of Erasthotenes recursively using filter and I was wondering how efficient this implementation is and wether a non-recursive implementation ...
3
votes
1answer
71 views
Adding an item to a hierarchical data structure
What I need to do is create a new object, modify it using a recursive function, then merge it with another object, and do this all in such a way that the values of the new object take precedence over ...
