# 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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### Efficient polynomial multiplication in Python

I'm practicing problems for the ICPC competition, and one of the problems requires solving it by using an FFT to compute the product of two polynomials efficiently. Since this is for the ICPC ...
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### BIO 2021 Q3a: Window Dressing (BFS in C++)

I was practicing question 3a of the British Informatics Olympiad 2021 past paper. A shop is looking to display some boxes (conveniently labelled A, B, …) in their window. There is a desired order for ...
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### BIO 2021 Q1a: Down Pat

I was practicing question 1a of the British Informatics Olympiad 2021 past paper. A pat is a single letter or a string of letters which can be split into a left and right string (of at least 1 letter)...
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1 vote
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### Finding the number of distinct decompositions a number has using only repdigits

This is a problem from a previous semester that I am trying to upsolve. I am trying to solve a problem involving the total number of ways of decomposing a number using only repdigits. A repdigit is a ...
736 views

### Finding the Zeckendorf Representation of a Positive Integer (BIO 2023 Q1)

I was practicing question 1a of the British Informatics Olympiad 2023 past paper. In the Fibonacci sequence each number is generated by adding the previous two numbers in the sequence. We will start ...
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### String Decryption in C (BIO 2022 Q1)

I was practicing question 1a of the 2022 British Informatics Olympiad past paper. Each letter in the alphabet can be given a value based on its position in the alphabet, A being 1 through to Z being ...
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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 ...
410 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 ...
43 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 ...
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### 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 ...
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### 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 ...
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### 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: ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
337 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 ...
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### 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 ...
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565 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),...
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### 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 (...
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### 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 ...
132 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 ...
570 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....
500 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 ...
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1 vote
215 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: - "()" ...
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### 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 <...
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 ...
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### 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 ...
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### 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 ...
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287 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: ...
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1 vote
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### 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 ...
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### 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 ...
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### 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 ...
1 vote
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### Determine top t values with few calls to order(), a given procedure to order k values, Java take 2

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 $k$ ...
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### Advent of Code 2023 - Day 19: Aplenty (Part 1)

Description: The task involves processing a set of workflows, each comprising rules. These rules define conditions based on part ratings and dictate the destination workflow if the conditions are ...
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113 views

### Delete a node in binary tree

Problem Statement Given a root node reference of a BST and a key, delete the node with the given key in the BST. Return the root node reference (possibly updated) of the BST. Basically, the deletion ...
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### Roman numerals look and say sequence

I was practicing question 1 of the 2020 british informatics olympiad past paper: The Roman look-and-say description of a string (of Is, Vs, Xs, Ls, Cs, Ds and Ms) is made by taking each block of ...
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### Advent of Code 2023 - Day 15: Lens Library

Part 1: The task involves initializing the Lava Production Facility using an initialization sequence. The sequence consists of steps, each requiring the application of the Holiday ASCII String Helper ...
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### Advent of Code 2023 - Day 9: Mirage Maintenance

Part 1: The task involves analyzing an environmental report from an oasis using the Oasis And Sand Instability Sensor (OASIS). The report consists of multiple histories, each containing a sequence of ...
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56 views

### Advent of Code 2023 - Day 8: Haunted Wasteland (Part 1)

Description: The task involves navigating a haunted wasteland on a desert island using a camel. The objective is to escape from the current position (AAA) to the destination (ZZZ) by following left/...
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163 views

### Codewars 4 Kyu kata: "Most frequently used words in a text"

This was the first kata I found hard so I wanted to ask about it. Any ways I could I have done it better? here's the question -> Most frequently used words in a text ...
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### Find median value of two Sorted Arrays

To improve my coding knowledge can you please give me suggested changes on my code? ...
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### Advent of Code 2023 - Day 6: Wait For It

Part One: The task involves organizing multiple toy boat races, each assigned a specific race time and a recorded distance. To surpass the existing record, participants must optimize the duration of ...
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### Advent of Code 2023 - Day 5: If You Give A Seed A Fertilizer (Part 1)

The task involves determining the lowest location number corresponding to a given set of seeds by following numerical mappings for soil, fertilizer, water, light, temperature, humidity, and location. ...
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### Finding the number of "block chains" that are a certain length and begin with a certain string

I'm currently practicing for the british informatics olympiad by doing past papers. I was doing question 3 of the 2019 paper: A set of children’s blocks, each illustrated with a single different ...
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### Advent of Code 2023 - Day 4: Scratchcards

Part 1: The task involves determining the total points of a set of scratchcards. Each scratchcard contains two lists of numbers: the winning numbers and the numbers the player has. Points are awarded ...
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### 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 ...
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1 vote
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### Advent of Code 2023 - Day 2: Cube Conundrum

Part 1: The challenge involves analyzing recorded games where an Elf reveals subsets of cubes in a bag, each identified by a game ID. The goal is to determine which games would be possible if the bag ...
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