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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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 ...
2
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1answer
61 views
Write a function that adds two numbers stored in a linked list and returns the sum
Just for fun I did the following exercise from "Cracking the coding interview. 4th edition":
You have two numbers represented by a linked list, where each node
contains a single digit. The digits ...
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0answers
28 views
Swift Knapsack problem using bottom-down (memoization) approach
I'm solving the "unbounded" variant of the knapsack problem, meaning the repetition of items is allowed. As in the Hackerrank version of the knapsack problem, I am returning the sum nearest to, not ...
3
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2answers
74 views
Find the longest sub string of a word after concatenation of given words array
An Array of N words is given. Each word consists of small letters ('a'-'z'). Our goal is to concatenate the words in such a way as to obtain a single word with longest possible substring composed of ...
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1answer
28 views
Recursive react.js navigation menu
I'm very new to React.js and have to start converting an entire website at my work. It's fun, but I'm hoping to get some feedback about how I tackled building this navigation component as I don't ...
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2answers
54 views
Recursive Transversal (Python)
For a programming challenge I was doing, I needed to traverse a list of lists, and while writing the standard 2D traversal function, I thought why not generalise it, so I did. Here's my best effort:
...
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0answers
38 views
Bin-packing-problem solution using recursion
I needed to make a freight calculator and had to solve a bin packing problem. I utilized a github package.
Basically with the help of my stack overflow question I made a class Method that
Splits an ...
2
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1answer
48 views
Most efficient way to find spatial order from a list of tuples (Python)
I have a circle-growth algorithm (line-growth with closed links) where new points are added between existing points at each iteration.
The linkage information of each point is stored as a tuple in a ...
4
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2answers
63 views
Computing bezier curves of degree n with recursive functions
I have been looking at homemade CNC and have been wondering how curves are drawn, so I looked into it and found this cool article. I then decided to try coming up with a bezier curve algorithm in C. ...
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1answer
60 views
Find first repeating Char in String
Given a string, find the first repeating character in it.
Examples:
firstUnique("Vikrant") → None
...
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2answers
63 views
Get property value from object tree in a recursive way
Consider the following structure,
let condition = { and: [ { id: 3 }, { pageId: '1' } ] }
I want to get the id property value ...
2
votes
1answer
42 views
Finding peak point in an array by using divide and conquer approach
It is to find the maximum element in an array which is first increasing and then decreasing. I've tried to write my idea by using divide and conquer approach. Is there any improvable or missing point? ...
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vote
1answer
64 views
Rectangle packing in smallest possible area
I have written a Java Program to place a bunch of rectangles
into the smallest possible rectangluar area(no overlapping and rotating).
Here is a short summary:
I calculate minArea and maxArea:
...
4
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3answers
113 views
Java Magic square program
Here is my improved version of my Magic square program from following this earlier version.
I also added a few comments.
Any help for improvements would be really appreciated.
...
4
votes
2answers
35 views
Replace array element with multiplication of neighbors in Scala
Given an array of integers, update the index with multiplication of previous and next integers,
Input: 2 , 3, 4, 5, 6
Output: 2*3, 2*4, 3*5, 4*6, 5*6
Following ...
3
votes
2answers
141 views
Knapsack problem - recursive approach with memoization
This post is based on the 0-1 Knapsack problem. I came across this problem in Assignment #4 of Professor Tim Roughgarden's course Greedy Algorithms, Minimum Spanning Trees, and Dynamic Programming on ...
2
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1answer
43 views
Java n-ary Tree class with custom made methods and nested Node class
I'm a beginner and I wrote this (working) code for n-ary tree.
The specifics:
Each node is to be built with an integer value.
Each node has a variable number of children.
The nodes should have an ...
2
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0answers
24 views
Finding first duplicated value from “circular” list with a recursive function
Background
This year I've taken on the challenge of Advent of Code. The second challenge of the first day is to calculate a frequency for a special device based on a series of numbers. Here's a quote ...
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2answers
38 views
Wrapping certain elements in an array with an array with PHP
I have a function that's doing this correctly, but I feel as though this can be done (possibly) with minimal code, with recursion, but I'm just wracking my brain. Basically I have JSON that gets ...
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2answers
89 views
A recursive algorithm to find the number of distinct quantities of money from a pile of coins
Problem: find the number of distinct quantities of money that a pile of coins can make.
The vector coins contains the values of the coins, and the corresponding ...
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1answer
40 views
Recursive loop which returns a value according to a single condition
I have a method that takes as parameter an array of several depth (group) and a name as a string (currentFilterName)
...
3
votes
1answer
133 views
Speed up Magic square program
I have written a Java program to calculate magic squares with recursion and backtracking. A 3*3 Magic square is calculated in about 1 sec, but a 4*4 needs about 50 minutes on my laptop with Intel i5. ...
1
vote
2answers
58 views
Recursive range iteration
I decided to do Advent of Code this year in D, and the following is my solution to day 8.
Algorithm aside, I was specifically wondering if there was a better way to use ranges in a recursive manner ...
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1answer
52 views
Binary Reflected Gray Code generation recursively
I tried to write BRGC recursively. I've really recognized that intrinsic of recursion helps for some problems in which I think BRGC is included. is the way I wrote it recursively adequate solution? ...
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3answers
216 views
Leetcode #91 - Number of ways to decode a string
I'm working on problem 91 on Leetcode.com called Decode Ways and I've successfully managed to get a working recursive solution but it results in Time Limited ...
2
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1answer
42 views
Search a list recursively and return the index of the smallest value
I was asked to define a function that takes a list as an argument and returns the index of the smallest value.
This is what I came up with:
...
3
votes
1answer
81 views
Checking whether given array is sorted by divide-and-conquer
I've written a code that I try to use divide and conquer approach to determine if the given array is sorted. I wonder whether I apply the approach accurately.
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2answers
165 views
Getting Pascal's triangle recursively in Python
I've been practicing recursion lately and wrote this code to get Pascal's triangle recursively.
How would you guys improve it ?
I don't really like the fact that the recursion goes for ...
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vote
1answer
62 views
Recursive trim() function to handle arrays and objects
I have come up with a recursive function which applies trim() recursively to all string members of an array/object.
I don't have any specific quandaries about my ...
3
votes
2answers
672 views
Insert a number in a sorted list and return the list with the number at the correct index
I feel like the title is a bit wordy. What I have defined here is a function that takes two parameters:
a list that contains valued sorted from smallest to biggest
a number to insert at the right ...
3
votes
1answer
104 views
Pouring water between two jugs to get a certain amount in one of the jugs (2)
I have been practicing recursion lately and I came up with this code to solve the water jug problem, given two jugs of volume jug1 and ...
5
votes
3answers
222 views
Picking the smallest value in a list using recursion
This is the code I wrote in order to find the smallest value in a list using recursion.However I feel like there would be a better way to do this?
...
1
vote
1answer
52 views
Check if list contains a pair which adds up to a given sum
Kindly review this scala code for given problem and suggest improvements.
Problem - Given an array of integers and a target sum, check if array contains a pair which adds up to sum.
Example -
<...
4
votes
3answers
265 views
Password generator with multiple charset
This is just straight bruteforce with the ability to select multiple charset for one word, being able to mash up the linearity with a modulo. This code is also posted on GitHub.
Generateur.h
...
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2answers
106 views
Fibonacci Nth term using tail recursion [closed]
I have created a program that prints the Nth term of the Fibonacci sequence. The fib function needs to use tail recursion. If what I have coded isn't tail recursion, I would like to know how to change ...
3
votes
2answers
118 views
Simple recursive transformation solution in Python
This simple Python code I wrote for a problem asked during an interview. The problem statement is:
Given a tuple (a, b), transform this into (c, d) by applying any of the two below operations ...
2
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0answers
33 views
Flatten Hierarchical Categories
I have an XLSX file that contains a hierarchical list of categories. Each category has a basic query associated with it. I need to flatten these categories which involves combining the categories. I ...
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votes
4answers
88 views
K&R Exercise 1-19. Reverse program input one line at a time
Intro
I'm going through the K&R book (2nd edition, ANSI C ver.) and want to get the most from it: learn (outdated) C and practice problem-solving at the same time. For that reason, I'm trying to ...
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votes
2answers
60 views
Collect members from custom tree nodes
In my program, I have a tree of Group nodes, each identified by their ImportId.
Each group has zero or more members, that I ...
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votes
2answers
2k views
Tower of Hanoi Recursive Implementation using Python with OOP
I have just finished a small program for Tower of Hanoi using recursion. I did it to practice OOP which I recently learnt. It took me about 2 hours to research about the recursive algorithm and write ...
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vote
1answer
101 views
C++ heap CPS: Continuation Passing Style with Recursion
I am willing to see how to write readable and efficient continuations on the heap in c++. I am not quite satisfied.
The following is just an exercise: it is coded for fun. I post the code here ...
6
votes
1answer
218 views
Tower of Hanoi in NASM Win64 Assembly
This program is an implementation of the classic puzzle Tower of Hanoi! This is my first mostly recursive Assembly program. Any advice and all topical comments on code optimization and conventions is ...
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0answers
88 views
Recursive object/array filter by key
I have some code that takes some JSON, parses it, and given an optional filter, will attempt to find any key (or nested key) that includes the filter (partial matching - it does not match values). The ...
5
votes
1answer
177 views
Recursive Fibonacci in Rust with memoization
I'm trying to come up with an "elegant" way of calculating Fibonacci for number in Rust, using recursion and memoization (self-imposed requirements).
This is what I have so far:
...
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vote
2answers
62 views
When given 7 letters, find all possible words with length 3 to 7
I am writing a program in JavaScript to find all possible words given 7 letters. The words have to be 3 or more characters, and for right now I am limiting it to 7 characters long. The code below ...
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1answer
113 views
Scheme function to duplicate every element of a list a specified number of times
This code takes a list and a integer and duplicates every element in the list the specified number of times.
...
5
votes
2answers
185 views
Finding all possible letter combinations from an inputted phone number
Prompt:
Given a string containing digits from 2-9 inclusive, return all
possible letter combinations that the number could represent.
A mapping of digit to letters (just like on the ...
3
votes
1answer
283 views
Find the kth-to-last element of a singly linked list
I wrote this code for finding the \$k\$th-to-last element in a singly linked list.
...
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0answers
265 views
Filling values for nested dictionaries
I have a text file where any name followed with sequence word is considered a dictionary. The task is to go through the keys and values of a particular dictionary, which is already identified, and see ...
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2answers
31 views
Extract and divide algorithm implementation in Elixir
I just started learning Elixir and stumbled upon this challenge over on Programming Puzzles & Code Golf. It is a well-suited task for beginners, so I chose to give it a go (to be clear, give it a ...
