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.
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questions
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1answer
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Longest Substring without Repeating Characters Problem - Kotlin Recursion
I am practicing coding questions on leetcode. I have been an OOP my whole career, and I am trying to wade into the dark abyss that is functional programming. So I am trying to do things purely ...
2
votes
1answer
39 views
Permutations with replacement in Python
Many a times, I've had the need to use a permutations with replacement function.
So, I've written a function to do just that:
...
2
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0answers
126 views
generic implementation approaches for a recursive function
Let's take the famous fibonacci problem as an example but this is a generic problem. Also, taking scala as the language as it's rather feature-rich. I want to know which solution you'd prefer.
we all ...
0
votes
1answer
74 views
Factorial number in Rust for learning purposes
I'm currently trying to learn the basics of the Rust programming language, to do this my first piece of code after the classic 'Hello World' was a simple recursive Factorial function.
This is the ...
7
votes
1answer
120 views
Printing the number of ways a message can be decoded
My below solution to the following problem is exceeding the maximum recursion depth. I am looking for any improvements which i can make.
Problem
Alice and Bob need to send secret messages to each ...
11
votes
5answers
2k views
Python: pass “mutable integer” in recursion
I'm working on some code to find the max depth/height in a tree. I came up with a recursive solution, and I find myself needing to pass an integer "by reference". Currently, I'm using a mutable ...
2
votes
2answers
90 views
Continued fraction with relative precision in Python
I have the following recursive function to compute the continued fraction:
$$s_i = \frac{a_{i}}{b_{i} + s_{i+1}}$$
The relative error is defined as:
$$\text{Delta} = \frac{s_n - s_{n-1}}{s_{n}}$$
...
4
votes
3answers
133 views
2
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1answer
65 views
Berlekamp–Massey Algorithm in Haskell
I was recently tasked to write an implementation of the Berlekamp–Massey algorithm (for GF2) from a given inductional proof and decided to fresh up on my Haskell, since converting a proof by induction ...
3
votes
3answers
305 views
Sudoku Solver questions on style and algorithm
I am working towards a CSC degree right now and wanted to try and practice writing good code that could be easily maintained and read in industry. I wrote the following program in Java that takes a ...
4
votes
1answer
115 views
Recursive function to get all Zendesk tickets
I'm developing a Python library to consume the Zendesk search API.
Problem is, Zendesk limits search results to 1000 items. Thus in order to get all the results if they are greater than 1000 I need to ...
2
votes
0answers
51 views
Kadanes algorithm implementation
I just wanted to ask the following question. I have solved Kadanes algorithm using the recursive approach as shown below. The implementation works
...
4
votes
1answer
117 views
Minesweeper - Python 3 (beginner)
I’ve just created Minesweeper game, which work perfectly fine (for me).
Any suggestions on how to improve this code would be greatly appreciate, in terms of:
Object-oriented
Array
Error handling
...
9
votes
1answer
262 views
Number in words: recursive function
I would appreciate some feedback on the below code I wrote for a Project Euler problem. The answer comes out correct but I'd like feedback on the design of the function and implementation of ...
1
vote
2answers
95 views
2
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2answers
50 views
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
49 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 ...
0
votes
0answers
85 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 ...
12
votes
5answers
4k 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
88 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
46 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
26 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
60 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
70 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
117 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
149 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 ...
6
votes
2answers
345 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
113 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
168 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
38 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, ...
1
vote
0answers
67 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
101 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
179 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
50 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
40 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
66 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
155 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
332 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, ...
9
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
138 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
222 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
1k 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
95 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
538 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 ...
