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.
863
questions
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0answers
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Quick sort maximum recursion depth [on hold]
i am trying to implement the quick sort algorithm.
However i am getting the following error
RecursionError: maximum recursion depth exceeded while calling a
Python object
...
0
votes
0answers
13 views
Leetcode Finding Maximum Area of Island Solution
Problem
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 ...
2
votes
1answer
29 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
3k 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
53 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 ...
4
votes
2answers
130 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
210 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
42 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
46 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, ...
9
votes
2answers
554 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
102 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
141 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
549 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
77 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
524 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 ...
0
votes
1answer
24 views
5
votes
2answers
339 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
112 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 ...
7
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 ...
4
votes
3answers
389 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
27 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
90 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
231 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
33 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
39 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
67 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
105 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
43 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 ...
2
votes
1answer
44 views
Convert Tail-Call Recursive Code to Loop [closed]
So, I'm in the midst of writing a programming language interpreter in Python, and one of the problems I'm concerned about is that since I've been using a lot of recursions to implement the interpreter,...
4
votes
1answer
158 views
Return all valid paren strings with a given length
The problem is
Given a non-negative integer n, return all valid parentheses strings
with n open parens and ...
6
votes
1answer
76 views
Rendering tree of nodes as string
I'm creating a debug-view for my expression-trees. They record each operation automatically in a tree that I am transforming into string so that I can see the exact ...
1
vote
1answer
38 views
Depth-first traversal implementation in Java (by recursion)
I implemented a recursive depth-first traversal, with all three traversal modes in this function. Is this the most succinct way to write the code?
...
0
votes
1answer
38 views
Delete directory tree function
I made this function to delete a directory with all its contents recursively, will it work as expected in a production environment ? is it safe ? I don't want to wake up one day with ...
4
votes
1answer
35 views
Processing file inclusion directives using mutual recursion
I am preprocessing a set of files where one file is included in another file with an include tag like shown below:
file A
...
4
votes
2answers
117 views
Roman Numbers - The Functional Way
Yet another exercise in converting values between the decimal and roman number systems.
I have tried the functional way.
Any comments are welcome - but I'm especially interested in answers focusing ...
5
votes
1answer
120 views
A cartesian product of tuples in C++17
I would like to write a function that computes a cartesian product of two tuples in C++17 (the tuples can be of type std::tuple or ...
5
votes
1answer
215 views
Best way to performance permutations
This has been my white whale for a while, the idea is convert all the symbols to the goal symbol using all the pieces.
I did an algorithm like 5 years ago (now is lost) and reach lvl 48 but got stuck ...
2
votes
3answers
111 views
Looking for all numbers where each digit is bigger than the previous digit
This is the "Increasing Number problem", where we are looking for all numbers with \$n\$ digits where each digit is bigger than the digit before it. Or in Mathematical therms where:
$$\mathit{...
17
votes
2answers
3k views
Simple recursive Sudoku solver
My Sudoku solver is fast enough and good with small data (4*4 and 9*9 Sudoku). But with a 16*16 board it takes too long and doesn't solve 25*25 Sudoku at all. How can I improve my program in order to ...
2
votes
1answer
59 views
Replacing MIN and MAX macros with type-safe, recursive templates of variable arity
I'm currently reading Mastering Perl for Bioinformatics; I'm using the book for learning bioinformatics while implementing the code in C++. I came across a situation where I needed to use the minimum ...
8
votes
1answer
199 views
Recursive parser from Binary to JSON output
Background
I got this interview test and got declined due to not meeting their expectations, but never got a reason on what was bad and how they solved it. I want to improve and learn something out ...
4
votes
2answers
65 views
Three stage Sudoku puzzle generator
This was my first time attempting a project like this, so I figured it would improve readability, and would also just be nice If I allowed each stage to be visualized.
Also, this only generates them, ...
3
votes
2answers
198 views
Counting the number of ways to decode a string
I am working on problem where I need to decode a string:
A message containing letters from A-Z is being encoded to numbers
using the following mapping:
'A' -> 1
'B' -> 2
...
...
1
vote
1answer
134 views
The quicksort algorithm in Haskell
I am learning Haskell programming language mainly from this source. And there I have encouraged with "an elegant" realization of the quicksort sorting algorithm (the Quick, sort! section). Here it is:
...
3
votes
2answers
146 views
Capitalize a sequence of lines entered via console input and print/return
I'm running through the popular python practice exercises located at github:
https://github.com/zhiwehu/Python-programming-exercises/blob/master/100%2B%20Python%20challenging%20programming%20exercises....
2
votes
2answers
45 views
Listing ordered components, recursively
I am trying to get ordered components of an interface properly without having a local variable orderedComponents outside, and here is my current code.
Reason is because orderedComponents will be in ...
1
vote
1answer
147 views
Finding pairs that add up to a given sum, using recursion
I'm currently tasked with using recursion to find pairs that add up to a given sum. How would I make the function recursiveFixedSumPairs function more efficient and truncate this code? Also, what is ...
3
votes
1answer
31 views
Python class which chains Google translations back and forth between two languages
I created a class which creates chained translations (for example, Japanese translated to English, then back to Japanese, then to English).
Some concerns:
Is my usage of recursion good?
Is the class ...
3
votes
1answer
89 views
React.js Nested Nav Bar
This was written for a coding challenge for a company I recently starting working for. I'm looking for any suggestions on how to clean up the code, as well as any issues anyone thinks may occur as it ...
2
votes
1answer
26 views
C Recursive Opendir Wrapper to Sort Directories First (ascending/descending)
A recent post on StackOverflow about a recursive directory listing which produced an unsorted mixed file/directory list, sparked the stray thought of "What would it take to write a wrapper for the ...
