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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votes
1answer
31 views
Given a digit sequence, print the possible decodings of the given digit sequence
Examples:
12 gives:
'AB' and 'L'
and
123 gives
'ABC', 'LC' and 'AW'
Here is my attempt:
...
-2
votes
0answers
14 views
What is the logic error in the given NQueen algorithm? [on hold]
I wrote the following code for NQueens. But I end up with wrong answer. Could some one help me find the error in this?
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votes
0answers
14 views
Ways to make this recursive function more efficient [on hold]
int exp (int a, int b) {
int result = 1;
if (b == 0) {
return 1;
}
return result * a * exp(a, b - 1);
}
I have a program that calculates ...
3
votes
2answers
74 views
Recursive functions for sorting
I made a few recursive functions for learning purposes which do a variety of tasks. Here is my current and functioning code:
...
11
votes
4answers
1k views
To understand what recursion is, you must first understand recursion
This is the second assignment for my CS2 course:
Write a recursive C++ function writeLine() that writes a character repeatedly to form a line of n ...
5
votes
1answer
67 views
Paint fill function
Implement the "paint fill" function of image editing programs: Given a
screen point and new color fill the surrounding area.
Any comments on the code below?
Time complexity: ...
1
vote
1answer
31 views
Find free username based on schema
Hopefully this is not too complicated. I have this code that will generate a username based on the pre-configured schema the admin types in. The fields they can use are:
...
0
votes
1answer
23 views
Temperature dependent 1-d conduction in Python? [closed]
I'm trying to write a Python code that is a numerical solver for 1-d heat conduction (using FVM) with a temperature dependent thermal conductivity. It looks like my main challenge now is getting rid ...
7
votes
1answer
493 views
An Army of Ones
I've been practicing using recursion lately and thought this was a case where it would prove really useful, is this good use or is there some superior non-recursive way to go about it?
Challenge:
...
2
votes
1answer
28 views
Find relative filenames recursively in Emacs
I have a set of directories. For each directory I have a set of relative file names. I would like to select any of these relative filenames using completion, and then later reconstruct the absolute ...
5
votes
4answers
371 views
Digital root recursive function
Haven't any experience writing recursive functions.(Generally tend to avoid them - not sure if that's a negative). What do you think about the following?
This is also my first time using JUnit, I'd ...
3
votes
1answer
59 views
5
votes
3answers
92 views
Tree structure with support for inorder and preorder traversal
I am learning Tree Data Structures and came up with this code for implementing basic Tree Node using class and performing various Tree based operations like Traversals and others. The code works ...
0
votes
0answers
22 views
Optimize CSS Rule Dumper
I have written the following Tampermonkey/Greasemonkey script. I am trying to obtain a list of all CSS rules for a page; across all stylesheets. As of now, I am just iterating over everything. Is ...
5
votes
4answers
374 views
Recursive Java Red-Black Tree
I've made an attempt at a recursive Red-Black tree in Java. I realise that some of my code could be condensed but I tried to favour readability with this code as Red-Black trees can be somewhat ...
1
vote
1answer
61 views
How can I reduce this code javascript code so it's not as repetitve?
I have a function which goes through every name in an object. This object has an array parameter materials which holds other objects. Those objects have the same array parameter which hold more ...
3
votes
0answers
37 views
Spiral Scanning for matrix using recursion
I have written code for scanning an N x M matrix in spiral order using a recursive function.
It uses 5 parameters - including 2 extra variables:
call to keep ...
1
vote
0answers
59 views
5
votes
2answers
143 views
Knight's Tour with Heuristics
When someone suggested that I solve Knight's Tour, I did so with heuristics and recursion.
It takes a lot of time to solve even a 8x8 board:
N-A1
N-C2
N-E1
...
N-E6
N-F4
Time ...
12
votes
3answers
167 views
N-Queens - Brute force - bit by bit
A discussion in The 2nd Monitor made me realize I had never 'solved' the N-Queens problem. Additionally, as I read up on it, I realized that the 64-squares in a chess board would work well if ...
4
votes
0answers
90 views
Project Euler #14 — longest Collatz sequence
I was reading this question and realized that I didn't know Python well enough to critique the algorithm. So I wrote a Java solution instead, which is inappropriate for that question. Since there's ...
1
vote
2answers
45 views
Parse a tree & return the various paths
Input:
{ 1: [2,3], 2:[4], 3: [5,6], 4:[6] }
Expected output:
[[1, 2, 4, 6], [1, 3, 5], [1, 3, 6]]
My Code:
...
2
votes
1answer
71 views
A prime number sieve using recursion
Out of curiosity, I built a recursive Sieve of Eratosthenes in Python and I was wondering how it could be improved for efficiency and how it can improved to be aligned with python best practices.
...
6
votes
1answer
41 views
'Tis the season for gift-wrapping
When reviewing a Graham scan convex hull algorithm implementation, I wrote the following function in an answer:
...
1
vote
0answers
40 views
AI for an online contest
I'm actually creating an AI for the online contest Vindinium. The fact is that's also an exam for my school because I'm going to have a note with that work.
I created an AI based on ants pheromones ...
12
votes
2answers
187 views
My recursive parser is wet behind the ears (well, it's not DRY at least)
I have an issue opened on GitHub since mid-November, to refactor & DRY up the Rubberduck Parser module (the idea is to model the code in a VBA project or code ...
7
votes
4answers
269 views
Calculating a specific entry in a Pascal’s triangle recursively
Our task was to calculate the entry of a Pascal’s triangle with a given row and column recursively. The triangle was specified in a way that the tip of the triangle is ...
3
votes
1answer
96 views
Rotate image 90 degree clockwise recursively
Previous question:
Rotate image 90 degree clockwise
In this code I have used tail recursive, which is bad. Time complexity is still \$O(N^2)\$, which is worse-case. The only good part is memory ...
3
votes
1answer
53 views
Getting rid of extra test during initialization of loop/recursion
I'm reluctant to ask this question. My code below works, it's intelligible, and it seems reasonably efficient. It's just that there's a trivial, nitpicky issue that's driving me crazy. The function ...
5
votes
1answer
66 views
Create a tree recursivly
I want to create a Treeview in C# which will group file by prefix (here the prefix is a marked by the separator _). The following files should give this tree:
...
5
votes
2answers
157 views
Rotate an image (2D array) by 90 degrees recursively with low memory usage
I'm looking for comments on coding style, passing arguments, ...etc.
...
0
votes
1answer
64 views
Recursive functions
I am using the following code which recursively executes function findWpisInZone(), code works fine, I just wondering if there is any better way to do it in JS,
...
12
votes
0answers
159 views
Object storing and retrieving using wildcard identifier
I'm writing an interpreter for a scripting language which allows objects to:
Have an alias
Be referenced using a wildcard
Contain child objects
Combination of all three above
For example:
...
2
votes
1answer
42 views
Memoization for calculating minimal traversal distance within a positive matrix
The code below is for calculating the minimal traversing distance from the top left point of the matrix to the bottom right point of the matrix.
GitHub
Here is the core functionality. Please note ...
1
vote
3answers
52 views
AudioMetaTagger: recursively read files and gather metadata
So the idea is to read metadata recursively in a chosen directory, load their metadata and display it into a table.
Here is the simplified example of what I am doing.
...
2
votes
3answers
69 views
Removing nested blocks from a string
I wrote this function in scala that uses tail recursion to remove nested blocks from a text.
Usage examples:
...
7
votes
2answers
195 views
Brainfuck interpreter in Haskell
Okay, so I just started learning Haskell around a week ago and this is my first real program that I worked on all of yesterday with a lot of help from IRC. I know that using indicies and arrays is not ...
6
votes
2answers
195 views
7
votes
3answers
541 views
Simplifying this factorial function
def factorial(t,n):
if n == 1 : return t
else: x = (t * (n-1))
n = n-1
return factorial(x,n)
print factorial(6,6)
I can't seem to figure out ...
10
votes
2answers
232 views
Validating a Binary Search Tree
This is an implementation of a function to check the property of a Binary Search Tree, that is:
the key in any node is larger than the keys in all nodes in that
node's left subtree and smaller ...
2
votes
0answers
100 views
GOF Composite Design Pattern Implementation Using Modern C++
After reading about the composite pattern from the GOF design pattern book, I thought to re-implement the code mentioned in the motivation section using the modern C++ concept/idioms. Below is the ...
4
votes
4answers
265 views
Get the environment variable's value
I've written a function which can get the environment variable's value. The input parameter would one of the following:
${machine}/bin
...
4
votes
2answers
50 views
Lopsided Trees and Recursion
The original problem is:
Define the height of a binary tree to be the number of nodes in the
longest path from the root to a leaf. The empty tree is considered to
have height 0. A node is ...
6
votes
3answers
811 views
3
votes
3answers
166 views
Miller-Rabin Recursive Primality Test
I'm working on a primality test and have written a recursive function that returns the value of the function
\$b^{q-1} \bmod q\$
where \$3<= q <= 32000\$
Is there any way to speed up ...
2
votes
1answer
613 views
Nsum problem: find all n elements in an array whose sum equals a given value
I am implementing the algorithm for the following problem with Python. I am pretty new to Python, so I want to listen to any advice that improve my coding style in a "pythonic" way, even about naming ...
5
votes
2answers
375 views
Simple factorial program using recursion
Two concepts I realized I needed to understand and use more are recursion and Exceptions. Thus, I combined both in the following program. Although it began with a focus on using recursion it became ...
4
votes
2answers
524 views
3
votes
3answers
292 views
6
votes
3answers
259 views
Recursive linear search - branch style and layout
Is my layout of the if/else statement reasonable?
It feels clumsy to me to spread the termination condition over the first three lines of the function. Can I ...
