Questions tagged [algorithm]
An algorithm is a sequence of well-defined steps that define an abstract solution to a problem. Use this tag when your issue is related to algorithm design.
5,062
questions
-2
votes
0
answers
37
views
Transportation problem & mathematical optimization [closed]
I have to find the solution for the transportation problem with some limitations.
Here we have basic table, where A is Supply column, B is Demand line and matrix has tariffs for transportation.
A(Sp)\...
5
votes
1
answer
289
views
Leetcode: Largest Number
I was trying out leetcode's Largest Number.
As per the challenge's description:
Given a list of non-negative integers nums, arrange them such that
they form the largest number and return it. Since ...
- 301
4
votes
0
answers
67
views
Implementation of Kirkpatrick-Seidel convex hull algorithm and comparing against Jarvis-March
Introduction
I wanted to implement the Kirkpatrick-Seidel(KPS) convex hull algorithm and chose Rust as my language. I referred to the original KPS paper and tried to implement as closely it as ...
- 233
4
votes
1
answer
64
views
Centre of mass based TSP solution (2)
I updated the code to a working state. My previous question. Even if this code working I wonder if I can write this code in a more efficient way. Maybe less for loops Etc.
...
- 51
8
votes
2
answers
413
views
Image Rotation and Transpose Functions Implementation in C++
This is a follow-up question for Gaussian Fisheye Image Generator Implementation in C++ and An Updated Multi-dimensional Image Data Structure with Variadic Template Functions in C++. I am trying to ...
- 4,708
4
votes
4
answers
1k
views
Creating an O(n) algorithm for an array of integers
To avoid plagiarism in my university, I am going to modify the problem.
Henry likes to jump from building to building. The heights of each building are given as a list of H numbers. We also number ...
- 41
7
votes
1
answer
239
views
Colorful Subgraph Dynamic Programming Solution and a Naive One
Given a graph \$G(V, E)\$ with vertices \$V\$ and edges \$E\$, where each vertex is associated with a single color from a set of colors \$C=\{1, 2, ..., k\}\$, we define the following problem:
Problem ...
0
votes
0
answers
38
views
Thread pooled bidirectional breadth-first search in Java for graphs with slow node expansion - part I/II: the algorithm
(This post has part II/II.)
Intro
This time, I have this GitHub repository. The idea is that if the graph node expansion is slow (for example, in the case where you ask a web server to return some ...
- 28.2k
3
votes
1
answer
81
views
Gaussian Fisheye Image Generator Implementation in C++
This is a follow-up question for An Updated Multi-dimensional Image Data Structure with Variadic Template Functions in C++ and Three dimensional gaussian image generator in C++. I am trying to make a ...
- 4,708
0
votes
0
answers
29
views
Efficient least-significant digit (LSD) radix sort for int and long keys in Java - iteration II
This post elaborates on Efficient least-significant digit (LSD) radix sort for int keys in Java. This time, I made mild corrections to my code and provided the radix sort for ...
- 28.2k
7
votes
3
answers
2k
views
Shunting yard calculator in C
I'm new to C, and made this program that parses a string expression into a linked list post-fix expression, and then evaluates it, without parsing the string beforehand. Wondering if there is anything ...
- 73
3
votes
1
answer
121
views
Efficient least-significant digit (LSD) radix sort for int keys in Java
(This post has a continuation post.)
This one is my attempt at LSD radix sort:
Code
com.github.coderodde.util.LSDRadixsort.java:
...
- 28.2k
3
votes
1
answer
85
views
Sorting songs with the ability to save and resume partial sorts
I listen to a lot of music (~4k h/y) and managing thousands of songs is a bit of a challenging.
To improve my listening experience I want to better organize my collection.
One thing I want to do is ...
- 43.3k
8
votes
2
answers
253
views
Filling a buffer with a repeating pattern of N bytes
My program will clear the screen to a 24bit RGB color; in other words, it will fill a buffer with a repeating pattern of 3 bytes. So I wrote patternMemcpy to perform this operation efficiently*. It ...
2
votes
3
answers
679
views
Step-by-step re-arranging of a string with randomized characters
A sloppy code featuring algorithms to efficiently randomize the characters of a string "Hello C" and then print out in the console the re-arrangement process for every character.
...
- 1,568
4
votes
2
answers
459
views
Leetcode: Steps to Make Array Non-decreasing
I was trying out leetcode's Steps to Make Array Non-decreasing
As per the challenge's description:
You are given a 0-indexed integer array nums. In one step, remove all
elements nums[i] where nums[i ...
- 301
3
votes
1
answer
116
views
RANDEVU - Rust crate implementing a simple algorithm I invented
I've created a simple algorithm which I've implemented in Rust and published it as a crate on crates.io.
https://crates.io/crates/randevu
While I do think my code is pretty clean and idiomatic, I ...
- 33
1
vote
0
answers
45
views
An Updated recursive_transform_reduce Template Function with Unwrap Level Implementation in C++
This is a follow-up question for A recursive_transform_reduce Template Function with Unwrap Level Implementation in C++. To fix the issue mentioned in G. Sliepen's answer, I updated the test cases and ...
- 4,708
2
votes
1
answer
44
views
A recursive_transform_reduce Template Function with Unwrap Level Implementation in C++
This is a follow-up question for A recursive_transform_reduce Function for Various Type Arbitrary Nested Iterable Implementation in C++ and recursive_invocable and recursive_project_invocable Concept ...
- 4,708
1
vote
3
answers
109
views
Find min sum for indices to match equation
I want to reduce time complexity of my code:
I have an array of integers arr say [1, 2, 3, 6, 67]
I have an equation :
a*x+b*y=z, I can use the array values in this ...
- 149
1
vote
0
answers
68
views
Skip list -based Map in Java
Now I have this result.
Code
com.github.coderodde.util.SkipListMap.java:
...
- 28.2k
9
votes
4
answers
2k
views
Leetcode : First Missing Positive
I was trying out leetcode's first missing positive.
As per the challenge's description:
Given an unsorted integer array nums, return the smallest missing
positive integer.
You must implement an ...
- 301
2
votes
1
answer
133
views
First order hidden Markov model with Viterbi algorithm in Java
Introduction
A first order HMM (hidden Markov model) is a tuple \$(H, \Sigma, T, E, \mathbb{P})\$, where \$H = \{1, \ldots, \vert H \vert\}\$ is the set of hidden states, \$\Sigma\$ is the set of ...
- 28.2k
1
vote
1
answer
101
views
Path Compression Algorithm in C#
Let's consider a simple graph represented by the following edges, where true indicates a visible node and false indicates a non-visible node:
...
- 141
6
votes
2
answers
335
views
A simple find function with concepts
I have written the following simple find function template that does a linear search.
...
- 757
2
votes
1
answer
78
views
Semi-dynamic range minimum query (RMQ) tree in Java
Introduction
I have this semi-dynamic range minimum query (RMQ) tree in Java. It is called semi-dynamic due to the fact that it cannot be modified after it is constructed. However, the values ...
- 28.2k
4
votes
1
answer
305
views
c++ quicksort pivots
Is this code for quicksort using the first index as a pivot correct?
Also if I want to use the last or middle index as a pivot how would the whole code change?
...
- 41
1
vote
2
answers
65
views
A recursive_find_if Template Function with Unwrap Level Implementation in C++
This is a follow-up question for A recursive_find_if_all Template Function Implementation in C++, A recursive_all_of Template Function Implementation in C++ and A recursive_all_of Template Function ...
- 4,708
4
votes
2
answers
140
views
Beginner's attempt at TicTacToe
This is my attempt at making a basic TicTacToe game to play against another human player or a computer controlled opponent. The project was a lot harder for me than I initially thought it would be!
I ...
- 55
1
vote
1
answer
97
views
Bit vector in Java supporting O(1) rank() and O(log n) select() - follow-up
(This post is the continuation of Bit vector in Java supporting O(1) rank() and O(log n) select(). It resides here (version 1.0.1).)
Basically, I have implemented everything harold suggested, except ...
- 28.2k
2
votes
1
answer
29
views
Simplify matching values while comparing two sorted sets
This is in Star Basic but most likely quite a few languages would have similar structure.
I am comparing rows in two sorted sheets. I have a comparison function which returns -1 / 0 / 1 similarly to <...
- 376
0
votes
1
answer
51
views
Performance optimization of traveling salesman like issue
I need help optimizing the performance of this, which is essentially similar to the traveling salesman problem, with the addition that I want to make the graph complete first, with the weight of the ...
- 109
1
vote
2
answers
113
views
Implement document processing system
I have to implement a class with method that takes document:
...
- 379
1
vote
1
answer
148
views
Bit vector in Java supporting O(1) rank() and O(log n) select()
Introduction
I have this GitHub repository (version 1.0.0.). It implements a rank(i) operation in \$\Theta(1)\$ time, and ...
- 28.2k
1
vote
1
answer
56
views
A recursive_find_if_all Template Function Implementation in C++
This is a follow-up question for recursive_any_of and recursive_none_of Template Functions Implementation in C++. I am trying to follow the suggestion of G. Sliepen's answer to implement ...
- 4,708
2
votes
2
answers
131
views
Map coloring algorithm functional implementation in python
I'm an autodidact working on map coloring algorithms with backtracking, see chapter 2 of this book.
I tested this implementation with success but I'm still unsure whether it is tricking me somewhere, ...
- 23
1
vote
1
answer
45
views
recursive_any_of and recursive_none_of Template Functions Implementation in C++
This is a follow-up question for A recursive_all_of Template Function Implementation in C++ and A recursive_count_if Function For Various Type Arbitrary Nested Iterable Implementation in C++. Besides <...
- 4,708
1
vote
2
answers
139
views
Fully generic, very efficient bidirectional Dijkstra's algorithm in Java
After finding out that my previous implementations are incorrect, I decided to give it another try. I relied on this post.
(The entire project resides in this GitHub repository. Contains some unit ...
- 28.2k
4
votes
1
answer
672
views
Caesar Cipher in Swift (iOS-app)
I have implemented the Caesar Cipher in Swift and incorporated it into an iOS-app.
I guess it's formally correct. Please see the attached images, which show how the usage of the app is meant.
Here's ...
- 4,294
4
votes
2
answers
427
views
Z-Function/ Algorithms on strings. C++
The problem:
Given a string s. For each i from 1 to |s|, find the number of occurrences of its prefix of length i in the string.
Input:
The first line of input contains an integer q (1≤q≤10⁵) — the ...
- 43
1
vote
0
answers
93
views
Generating group permutations: an extended Heap's algorithm in Java
Suppose we have a sequence of sequences <1, 2> <3, 4>. There, we have two groups: <1, 2> and ...
- 28.2k
8
votes
2
answers
399
views
Heap sort optimization
I tried to optimize heap sort algorithm. Instead of recursion, I used iteration:
...
- 121
4
votes
1
answer
92
views
Generic Algorithm X implementation with dancing links (DLX)
This is a generic implementation of Knuth's "Algorithm X" using dancing links. The whole code with a "mandatory" sudoku solver can be found at gitlab.
Regarding the scope of the ...
- 7,250
1
vote
0
answers
67
views
Nodejs Websocket pulling new data from InfluxDB
I have a nodejs server with websocket which is pulling the new data from InfluxDB and send it to client.
The piece of code is this:
...
- 111
0
votes
0
answers
66
views
Is this iterative inorder traversal algorithm well-known?
I was concerned about the approach in Morris traversal algorithm and came up with simpler solution that uses parent pointers in nodes.
The constraints were following:
Time Complexity: O(n)
Space ...
- 1
2
votes
1
answer
99
views
Move timestamp to the next Monday 10:01 AM [closed]
I've been battling ChatGPT for hours now and can't get satisfied with this simple algorithm in TypeScript. These two (hopefully correct) TypeScript+ReactNative solutions should move the timestamp ...
- 121
7
votes
2
answers
2k
views
Gaussian elimination algorithm in C++
Given:
j-g-h-i=0
a+b-c-j=0
c+i-d-e=0
e+g-f=0
And known:
a=10
b=7
d=3
e=2
f=3
j=14
I want to solve this (or similar equations) ...
- 464
3
votes
1
answer
144
views
Pentomino solver in Python
When I was a child, I used to play Ubongo board game, recently I discovered Pentomino puzzle and I wanted to create a custom solver in python for it. Here is what I got:
...
- 31
1
vote
1
answer
82
views
HackerRank Algorithm Problem: Climbing the Leaderboard (Python)
Here is the Hackerrank problem which is related to dense ranking and below is my solution which didn't pass the time limit cases. Any better way to optimize this?
...
- 57
2
votes
1
answer
68
views
Creating Worst-Case Scenario for QuickSort using Middle Pivot in Java
I've implemented a solution to generate the worst-case scenario for QuickSort using the middle pivot strategy in Java. The goal is to rearrange an input array to produce the worst performance during ...
- 21