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.

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Using Token Bucket to rate limit function calls

This program is my attempt at solving the below problem: We have a function which is going to be called by multiple threads. The problem is to find a way to limit the number of times this function is ...
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177 views

10 Kinds of People Open Kattis Problem Time Limit Exceeded C++

I am trying to solve the open kattis problem '10 kinds of people' (https://open.kattis.com/problems/10kindsofpeople) using a best-first search algorithm and c++. 10 Kinds of People The world is made ...
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150 views

Finding sum in an array

I have this program finding 2 numbers in the array (unsorted) so that its sum equal to the target sum. Here is my program: ...
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1answer
56 views

Number of inversions on a segment

I was trying to do this question and I get TLE on one the test cases (the actual link to the question will ask you to login). What is an inversion? An inversion of an element is the number of ...
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Algorithm to find bucket and item indices from power of two bins?

So this is building off of Algorithm for dividing a number into largest "power of two" buckets?. Here is a slight modification of the answer from there: ...
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1answer
56 views

Marching Square algorithm (2)

The following source code is a solution to the Marching Square problem. The explanation of using random numbers in ambiguous cases can be found here. ...
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1answer
78 views

Mergesort in python

My mergesort implementation currently takes a very long time, for a list with 1 million elements it takes over 130 seconds to get the list sorted. Could someone kindly have a look at my code and ...
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1answer
61 views

Checking if a value is in the RGB range and then increment/decrement

Is there a better way to check if the variable x is in the 0-255 range and: if x is less than 255, add ...
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1answer
45 views

Binomial Expansion Calculator

So i wrote a program with the documentation for my fx cg50 calculator's micropython to calculate various items, each of which are: Pascal Triangle Entry Pascal Triangle Level/Entire Row Binomial ...
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3answers
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Efficiently calculate the value of an arithmetic sequence

I need to calculate the value for the following function: $$f(n) = -1 + 2 - 3 + ... + -1^n$$ The time limit to calculate a given value of \$n\$ is less than 1 second. My approach does not meet that ...
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1answer
56 views

Projecteuler.net Problem 2 using collection pipeline Pattern

I solve projecteuler.net Problem 2 deferent way Generate number from 1 to range ex 100 and get the even number Get Fibonacci numbers from list Reduce array I have one problem with a large set of ...
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Is the following divide and conquer recursive algorithm for the exponentiation more efficient than the iterative one for large numbers?

I have the two following algorithms. My analysis says that both of them are \$\mathcal O(m^24^n)\$ i.e they are equivalent for big numbers (more than 32 bits). Is this right? Note that ...
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1answer
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Sudoku Solver using rules of Sudoku and backtracking

This code tries to solve the sudoku board using the rules of sudoku. When it does not make progress in solving, it assumes a cell value and tries again. Please review my code and help me understand ...
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1answer
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Data analysis code (finds coincidences in three sets of data)

I've written the following data analysis code (using just a couple lines from CERN's ROOT data analysis framework). It's designed to find coincidences in three sets of data (timestamps from an ...
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1answer
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Multiple Pandas Ranking Operations within a Loop - Better Optimization and Performance

I have implemented the following code which works as intended. However, I would like to improve my code in terms of performance and efficiency Code in Question ...
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2answers
78 views

Different approach Union Find

I am studying algorithms and I did this "Union Find Like" algorithm. I have one array of objects with a reference and I make the union pointing to the same reference instead of have two int[]...
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1answer
75 views

Sorts and data structures: a bucket sort

I am currently going through and implementing basic algorithms and data structures as I feel I didn't learn enough about this during my Data Structures and Algorithms unit. So far I've done the ...
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Kattis: “watering Grass” Interval covering problem, why is my code so slow?

im currently practicing, doing a python implementation of this challenge: https://open.kattis.com/problems/grass Problem described here: ...
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Insertion sort for std::forward_list

I'm practicing writing insertion sort for std::forward_list. But I find myself creating many variables and using many if statements. Looking for inputs on how to make the function more efficient, ...
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C++ chess game engine using Minimax and alpha-beta pruning;

My chess game is over, everything has been finished, except for some special (like en passant)moves. The main part of the game is its engine which I have coded using the Minimax algorithm with alpha-...
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Finding strongly connected components in a directed graph using Kosaraju's algorithm

I'm working through Stanford's algorithms course on edX. One of the programming assignments is to find strongly connected components using Kosaraju's algorithm, on a graph with ~875,000 vertices. My ...
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2answers
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Exponentiation by squaring in x64 Linux Assembly

I am learning some assembly for a compiler project I am working on and I have come across the Exponentiation by Squaring algorithm when it came to calculating x ^ n. To get a grasp on how the ...
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JavaScript Priority Queue implementation using a binary heap

I'm currently going over Robert Sedgewick's Algorithms book. For the implementation of A priority queue using a binary heap I implemented the code using ES6. I believe to have more experience with ...
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1answer
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Bubble Sort In C++

I'm learning modern C++ and also algorithms, and am doing some practice by coding up some simple algorithms. Also trying to use templates whenever possible as I'm quite unfamiliar with generic ...
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1answer
141 views

Scan-line algorithm to fill in a triangle

I wrote the following script to fill a Triangle. ...
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1answer
139 views

Python: Astar algorithm implementation

I have implemented Astar algorithm for a problem on an online judge relating to maze given start and end positions along with a grid representing the maze. I output the length of the path along with ...
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1answer
174 views

Memory/Time usage on substring search code

I have implemented a substring search, which works as expected and provides the right output. On some edge cases tho, I get either Memory or Time limit exceeded because: the string length is too big ...
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2answers
148 views

Sum of 2 numbers in an array [closed]

I have this problem to solve: Given an integer \$z\$ and an array \$a\$ of distinct integers sorted in ascending order, find two numbers, \$x\$ and \$y\$, belonging to the array such that \$x + y = z\...
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1answer
104 views

Sentinel linear search

I'm pretty new to algorithms, and it's my first attempt to implement sentinel linear search in JS. I'm wondering if it can be improved. ...
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Can I draw a square with pixels more efficiently?

I'm drawing a square on a window using an implementation of Xlib. I put a colored pixel with my_pixel_put at a specific (...
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0answers
62 views

Marching Square algorithm

The following source code is a solution to the Marching Square problem. The explanation of using random numbers in ambiguous cases can be found here. ...
4
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2answers
237 views

Floyd-Warshall Path Reconstruction

Below is the implementation for the Floyd-Warshall algorithm, which finds all-pairs shortest paths for a given weighted graph. The function floyd_warshall takes a ...
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LeetCode 146: LRU Cache (Go)

Posting my code for LeetCode's LRU Cache, if you'd like to review, please do so, thank you for your time! Problem Design and implement a data structure for Least Recently Used (LRU) cache. It should ...
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1answer
38 views

Selection Sort Java and Analysis

I have written a selection sort code in java. I know its very elementary algorithm, but since i am learning, so wanted your input about the quality of the code. Please have a look at the code: package ...
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1answer
60 views

Priority Queue implementation for top k frequent elements leetcode in Ruby

While working on the following leetcode problem: https://leetcode.com/problems/top-k-frequent-elements/ I used a Priority Queu implementation in Ruby. I have learned how to implement a Priority Queu ...
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1answer
28 views

Update UNIX-like system user profile picture with its GitHub account's one

Seeking to learning and have fun, I wrote out this script (what I expected to be) self explanatory and would appreciate some comments on that. I published it as a gist and tried to do my best on what ...
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1answer
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LeetCode 310: Minimum Height Trees

Posting my code for a LeetCode problem, if you'd like to review, please do so. Thank you for your time! Problem For an undirected graph with tree characteristics, we can choose any node as the root. ...
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A* using a Priority Queue

I've implemented an A* with a priority queue. I am not getting any performance issues in this little game that I am making but it would be interesting to know how to improve this. I am doing a few o(n)...
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1answer
47 views

LeetCode 1206: Design Skiplist

I'm posting my code for a LeetCode problem. If you'd like to review, please do so. Thank you for your time! Problem Design a Skiplist without using any built-in libraries. A Skiplist is a data ...
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2answers
165 views

C++ Practice on STL templates and algorithms

I have implemented the following program below for an assignment for practice on STL templates and algorithms. All I'm doing is implementing the code for the printing of empty files, un-empty files, ...
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Optimizing performance of randomly generated pygame maze game

I made a random maze generator that is also playable. The performance is crap and I'd like to improve it. I'll be working on this for a few more days to make it run better myself, but just thought I'd ...
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0answers
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Smashing two heaviest stones until at most one stone is left - counting number of stone comparisions

Based on this question: Heaviest Stone algorithm time complexity Problem: We have a collection of stones, each stone has a positive integer weight. Each turn, we choose the two heaviest stones and ...
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2answers
34 views

Merge Sort Implementation and Optimization

This is Merge Sort that i implemented, i feel i can make it better esp the combination function. So i split the code into functions because i don't like seeing a bunch of spaghetti code in a single ...
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0answers
46 views

LeetCode 1263: Minimum Moves to Move a Box to Their Target Location ||

I'm posting a follow-up code on this question, which seems to be a version of Sokoban. If you'd like to review, please do so. Thank you for your time! Problem Storekeeper is a game in which the ...
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80 views

Ugly Number problem using dynamic programming

I am learning Dynamic Programming and tried to solve the nth ugly number problem using it. Here's my code for the problem in Java: ...
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1answer
102 views

In-place merge two sorted array

First post. Can you please review my code and help me improve my coding. Please also suggest improvements if there is a miss in this post. Problem Statement Given two sorted arrays ...
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1answer
62 views

LeetCode 1263: Minimum Moves to Move a Box to Their Target Location

I'm posting my code for a LeetCode problem. If you'd like to review, please do so. Thank you for your time! Problem Storekeeper is a game in which the player pushes boxes around in a warehouse trying ...
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2answers
60 views

Line wrapping text utility using fixed-size arrays

As an exercise, I've made a text processing utility that wraps arbitrarily long lines of text, but only using fixed-size arrays and other basic C features. I have mostly programmed in Python, C++ and ...
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1answer
73 views

LeetCode 928: Minimize Malware Spread II

I'm posting my code for a LeetCode problem. If you'd like to review, please do so. Thank you for your time! Problem (This problem is the same as Minimize Malware Spread, with the differences bolded.) ...
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1answer
72 views

LeetCode 839: Similar String Groups III

I'm posting my code for a LeetCode problem. If you'd like to review, please do so. Thank you! Problem Two strings X and Y are similar if we can swap two letters (in different positions) of X, so that ...

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