# Questions tagged [programming-challenge]

Use this tag when the code is a solution to a programming challenge. Always include a sufficient description of the problem to be solved - while a link to the challenge is welcome, the review request needs to be complete when the challenge site is unavailable.

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### Project Euler 127 - abc-hits

Problem (Rephrased from here): The radical of $n$, $rad(n)$, is the product of distinct prime factors of $n$. For example, $504 = 2^3 × 3^2 × 7$, so $rad(504) = 2 × 3 × 7 = 42$. We shall ...
382 views

### Family, felon & fuzz River Crossing challenge

I first saw this challenge when a user posted it to SO about two years ago without a shred of code. The post's plea, "How do I get started?" meant the user's post didn't survive long on that ...
34 views

### Optimal Extraction of Longest Sorted Sequence from Individually Sorted Bucket Arrays Without Repetitions

Consider a bucket array containing sorted and/or empty buckets, and the goal is to extract the longest possible sequence in sorted order, under the following conditions: Only one element in each ...
119 views

### Performance Tuning to enable answer for Project Euler #566 "Cake Icing Puzzle"

Related to this question I am still looking for a solution to Project Euler Problem 566 (see link for a nice simulation also): Adam plays the following game with his birthday cake. He cuts a piece ...
214 views

### Leetcode: Number of Islands - BFS (Queue vs Recursion)

I was playing around with leetcode's Number of Islands. As per the challenge's description: Given an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), return the ...
4k views

### Find the longest word's length

The challenge is simple: Return the length of the longest word in the provided sentence. The solution is just as simple: ...
9k views

### Printing longest sequence of zeroes

I am doing a coding exercise in codility and I came across this question: A binary gap within a positive integer N is any maximal sequence of consecutive zeros that is surrounded by ones at both ...
69k views

### Find the repeated elements in a list

You are given an array of n+2 elements. All elements of the array are in range 1 to n. All elements occur once except two numbers, which occur twice. Your task is to find the two repeating numbers. ...
7k views

Introduction This problem is essentially equivalent to this HackerRank problem. The task is to remove all duplicate characters that are adjacent to each other in a given ...
596 views

### Count the occurence of nucleobases in DNA string

Inspired by this meta question I decided to take a look at Rosalind. Their first challenge seemed easy enough: An example of a length 21 DNA string (whose alphabet contains the symbols 'A', 'C', 'G', ...
563 views

### Advent of code 2023 day 5 in Java: mapping integer ranges to new integer ranges

Context I'll be passing an interview coding test in java soon. I am experienced with other programming languages but am very unfamiliar with Java. I am looking for critiques of the coding style much ...
5k views

### Cracking the Coding Interview: "Problem 1.5. One Away"

I am going one-by-one through problems in the "Cracking the Coding Interview". This question is about problem 1.5. One Away. Since I was never good in "algorithming", any suggestions are highly ...
88 views

### Optimizing a Function to Check Pronic Numbers in JavaScript

I've written a function in JavaScript to check whether a given number is a Pronic number. A Pronic number, also known as an oblong number, rectangular number, or ...
347 views

### Leetcode - First Unique Character in a String

Given a string, find the first non-repeating character in it and return its index. If it doesn't exist, return -1. Examples: ...
56 views

### Optimizing a Function to Generate a Row of Consecutive Odd Numbers in a Triangle

I've written a JavaScript function that generates a row of consecutive odd numbers in a triangle. The triangle looks like this: ...
1 vote
1k views

### Leetcode 55. Jump Game solution

I was working on Jump Game problem on leetcode Question You are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your ...
336 views

### Coding challenge for mixing a string

Challenge at https://www.codewars.com/kata/5629db57620258aa9d000014/train/python Given two strings s1 and s2, we want to visualize how different the two strings are. We will only take into account ...
93 views

### Coding puzzle - Passing year books

Question: There are n students, numbered from 1 to n, each with their own yearbook. They would like to pass their yearbooks around and get them signed by other students. You're given a list of n ...
859 views

### Given an array of N elements, answer Q queries asking if there exist two elements from two specified range with a given XOR value

We have array of N (≤10⁵) elements with Q(≤10⁵) queries. Each query is of type: p q r s x, where we have to find if there exist a element from array in range ...
1k views

### Project Euler #19: Counting Sundays in the 20th century using Pandas

Project Euler #19 asks: How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)? I'm hoping I wasn't too off course from the spirit of the exercise ...
1 vote
118 views

### Sum of differences between products and LCMs

I've been trying to solve this Codewars problem https://www.codewars.com/kata/56e56756404bb1c950000992 In this kata you need to create a function that takes a 2D array/list of non-negative integer ...
277 views

### Refactor the code which performs "cross-product", "reduce", "product of list" and "sum of list"

I have come up with a sequence of steps to find the maximum product of y positive numbers which add up to x. But the program is ...
113 views

### Finding cheapest route (turn costs 500, going straight costs 100)

Story Original link written in korean Jordi, the architect of a construction company, received a request from a customer for an estimate for the construction of a raceway. According to the raceway ...
331 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 ...
233 views

### Find the number closest to 0, breaking ties in favor of positive numbers

I'm a Perl beginner, I really love this language, and I was wondering if it was possible to reduce the size of this code, just for fun and so as to learn Perl specificities: ...
156 views

### Last Stone Weight Problem in Haskell using list insert

Background Saw this problem on TheJobOverflow which seems to be a LeetCode question. It bothered me that the "challenge" of this problem was to recognize the need for a specific data-type (...
31 views

### Last Stone Weight Problem in Haskell Using fold

A previous solution of this code has been posted on Code Review before. This solution is more complicated then that one, but more performant (see the below) Why is this another Question instead of a ...
71 views

### Sum all numbers touching symbols in 2D grid (Advent of Code 2023 Day 3, Part 1)

Please offer suggestions to my below Rust approach for solving AoC 2023 Day 3, Part 1. The code is functionally correct, so I'm interested in understanding how I could have solved it in a more ...
562 views

### Extract data from poorly formatted phonebook

The Problem John keeps a backup of his old personal phone book as a text file. On each line of the file he can find the phone number (formated as +X-abc-def-ghij where X stands for one or two digits),...
131 views

### Longest spell to cast from pages of spellbook follow-up

This question is from the PCTC 2022 R2 Past Paper and is a follow-up on my previous question. Previous question I have implemented several solutions suggested, such as creating an array with pages ...
563 views

### Longest spell to cast from pages of spellbook

While practicing for a school coding challenge, I came across this problem. My code got the right answers but exceeded the time limited. Any tips for how to reduce the time complexity? https://pctc....
491 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 ...
315 views

### Project Euler # 38 Pandigital multiples in Python

Take the number 192 and multiply it by each of 1, 2, and 3: 192 × 1 = 192 192 × 2 = 384 192 × 3 = 576 By concatenating each product we get the 1 to 9 pandigital, 192384576. We will ...
1 vote
213 views

### LeetCode 856: Score of Parentheses

Given a balanced parentheses string s, return the score of the string. The score of a balanced parentheses string is based on the following rule: - "()" ...
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 ...
1 vote
122 views

### Optimizing an algebraic assignment puzzle

I am going to do a math competition which allows writing programs to solve problems. The code attempts to solve problem 25 from the Purple Comet Spring 2004 Mathematics Meet: In the addition problem <...
280 views

### Sum of bitwise XOR of each subarray weighted by length

here is the problem statement You are given an array a of length n consisting of non-negative integers. You have to calculate the value of $\sum_{l=1}^n \sum_{r=l}^n f(l,r)\cdot (r - l + 1)$ where \...
1 vote
85 views

### Advent of Code 2023 day 1: Trebuchet (Part 2)

Task: The task involves analyzing a calibration document containing lines of text. Each line represents a calibration value that needs to be recovered by extracting the first and last digits (which ...
1k views

### Advent of Code 2023 day 1: Trebuchet (Part 1)

Task: The task involves analyzing a calibration document containing lines of text. Each line represents a calibration value that needs to be recovered by extracting the first and last digits and ...
284 views

### Count frequency of words and print them in sorted order

Objective: Write a program to count the frequencies of unique words from standard input, then print them out with their frequencies, ordered most frequent first. For example, given this input: ...
213 views

### Advent of Code 2023 day 1: Trebuchet (Part 1 and 2) Follow-up

This is a follow-up to the question asked here: Advent of Code 2023 day 1: Trebuchet (Part 1 and 2) Changes made: The code no longer assumes that all lines will fit into a fixed-size buffer. Although ...
2k views

### Reverse the digits of an Integer

Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321 Return 0 if the result overflows and does not fit in a 32 bit signed integer This is my approach: <...
121 views

### Locate and multiply numbers in a 2D grid (Advent of Code 2023 Day 3, Part 2)

I am using the Advent of Code 2023 to study functional programming and the ranges library in C++. This code is for the second part of Day 3 and is the best solution using FB I've created. I'd ...
1 vote
130 views

### Read millions of integers from stdin and process them in Python within 2 seconds

This is a competitive programming problem which has never been solved in Python within the time limit of 2 seconds. It is about Disjoint Set Union: Source: Algorithms In Context #10: Disjoint Sets ...
1 vote
495 views

### An implementation of Uber's "Fare Estimator" [CodeSignal]

CodeSignal put out a challenge by Uber that involves writing a "fare estimator" that involves a function dependent on cost per minute, cost per mile, ride time and ride distance. The formula ...
4k views

### Finding the position in a triangle for the given challenge

The LAMBCHOP doomsday device takes up much of the interior of Commander Lambda's space station, and as a result the prison blocks have an unusual layout. They are stacked in a triangular shape, and ...
707 views

### Making a Rock Paper Scissors game in Python - How to reduce repetition and make it more effective?

I am a "new" coder to Python - saying this because I got stuck in the tutorial hell - and I saw that doing projects was a way of consolidating what I had learnt from those tutorials, so here ...
482 views

### Increment a large integer represented as array of digits

This problem can be found at LeetCode. Since I was studying idiomatic or 'pythonic' code in my language today, I decided to take the most 'pythonic' approach and challenged myself to do this in one ...
1 vote
My 2nd take of the problem in Determine top t values with few calls to order(), a given procedure to order k values: Given an array and a procedure to order $k$ ...