# Questions tagged [programming-challenge]

Programming challenges are off-site challenges meant to offer programmers educational experiences while testing their abilities.

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52 views

### HackerRank New Year Chaos: arriving at a given list using neighbor swaps

I am trying to solve the HackerRank New Year Chaos problem where the aim is as follows: A vector of size n is having values ...
222 views

### Longest Substring Without Repeating Characters in JS

The task is taken from leetcode Given a string, find the length of the longest substring without repeating characters. Example 1: Input: "abcabcbb" Output: 3 Explanation: ...
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The task is taken from leetcode You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single ...
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I have some imminent interviews and want to sharpen my game before going into them. I'm running through some practice problems. This LeetCode challenge is to add two numbers represented as linked ...
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### Find common characters (LeetCode)

The task is taken from leetcode Given an array A of strings made only from lowercase letters, return a list of all characters that show up in all strings within the list (including duplicates). ...
55 views

### Find amounts that cannot be composed using the given coins

I need to make a program that receives a set of currencies and tests which values between 1 and 10,000 units can not be produced with these currencies. The program must have 2 input data: The ...
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### Leetcode: Find-bottom-left-tree-value

https://leetcode.com/problems/find-bottom-left-tree-value/ Given a binary tree, find the leftmost value in the last row of the tree. Example 1: Input: ...
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### Project Euler #357: Prime generating integers

Project Euler Problem 357 asks: Consider the divisors of 30: 1,2,3,5,6,10,15,30. It can be seen that for every divisor d of 30, $$d+30/d$$ is prime. Find the sum of all positive integers n ...
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### Writing billions of lines to text file in java [closed]

I'm trying to write billions of strings lines to a file, it works for up to 40 million lines, but it's throwing out "java.nio.BufferOverflowException" error for 400 million lines. I also think my ...
448 views

### CodeChef Matches challenge

I am solving some problems from CodeChef but I am stuck on the Matches problem: Ari and Rich are playing a pretty confusing game. Here are the rules of the game: The game is played with ...
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Exercise: Using a read7() method that returns 7 characters from a file, implement readN(n) which reads n characters. ...
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### Pascal's Triangle Java (performance)

I need to get some information about the Pascal Triangle. What is a pascal triangle ? It is a triangle of integers with 1 at the top and at the sides. Any number inside is equal to the sum of the ...
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### LeetCode: Employee-importance BFS

You are given a data structure of employee information, which includes the employee's unique id, his importance value and his direct subordinates' id. For example, employee 1 is the leader of ...
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### Cyclic queue using an array

I tried to implement a cyclic Queue using an array, as a task from a coding interview. Please comment about style, as well as any edge cases I may have missed. ...
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### Project Euler Task 42 Solution

I am relatively new to programming and have been recommended to work through the many tasks in order, in order to better my skills. For some reason, problem 42 had me stumped for a while: The nth ...
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### Hackerrank.com - Sherlock and Anagrams

Summary: Given a string find the number of anagramic pairs of substrings of it. e.g 'abba' pairs are [a,a],[b,b],[ab,ba],[abb,bba] so we have 4 pairs. I'm wondering if anyone can help me improve my ...
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The task is taken from leetcode There is a robot starting at position (0, 0), the origin, on a 2D plane. Given a sequence of its moves, judge if this robot ends up at (0, 0) after it completes ...
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### LeetCode: N-ary Tree Level Order Traversal

https://leetcode.com/problems/n-ary-tree-level-order-traversal/ Given an n-ary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example, ...
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### LeetCode: maximum-depth-of-n-ary-tree

https://leetcode.com/problems/maximum-depth-of-n-ary-tree/ Given a n-ary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the ...
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### Go - avoid result reassignement in OOP [duplicate]

I'm learning Go and I wrote this for a programming challenge. It is working (building and running) but I feel the code is not what Go code should be: The code implements the steps a podracer takes to ...
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### Simulating pod racing over a 2D map : am I implementing OOP in a GO-like fashion?

I'm learning Go and I wrote this for a programming challenge. It is working (building and running) but I feel the code is not what Go code should be. I used an OOP design. Is it correctly implemented ...
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### Flipping an Image

The task is taken from leetcode Given a binary matrix A, we want to flip the image horizontally, then invert it, and return the resulting image. To flip ...
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### Leetcode - First Unique Character in a String

Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Examples: ...
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### Foobar Challenge: Lovely Lucky Lambs

I've been able to reduce my solution to constant time. Is it possible to reduce this by any constant factor further? (Besides trivialities i.e. inserting constants, not lazy importing). Specifically, ...
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### Largest Palindrome Product - Project Euler #4

This is my code for Project Euler Problem #4 The question: A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99. ...
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### Finding largest number we can make

The problem is from yesterday's contest from Codeforces. I have observed that, from the left side (i.e. MSB), for every digit, if we replace the given number with the output of ...
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### Find number of islands Leetcode

Here is the question: Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally ...
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### Project Euler 76: Counting summations

Project Euler Problem 76 asks: How many different ways can one hundred be written as a sum of at least two positive integers? My code is correct but just works slowly. ...
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### Split string into as few substrings as possible such that each substring is a palindrome

The task Given a string, split it into as few strings as possible such that each string is a palindrome. For example, given the input string racecarannakayak, return ["racecar", "anna", "...
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### Straightforward tax calculator OO design

Similar questions have been asked here before and my solution is pretty much in line with some of the answers. I wanted to work on this a bit. Scenario Basic sales tax is applicable at a rate ...
79 views

### Rotate a linked list to the right by k places

The task Given a linked list and a positive integer k, rotate the list to the right by k places. For example, given the linked list 7 -> 7 -> 3 -> 5 and k = 2, it should become 3 -> 5 -> 7 ...
117 views

### Hackerrank: Computer Game (max-flow problem with integer factorization)

I am working on a coding challenge from the Hackerrank site. Given two equal-length arrays of integers, with values from 2 to 109, find the maximum number of times we can remove a pair (Ai, Bj) where ...
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### A faster way to compute largest prime factor (Again, but a lot better)

I came up with this code after implementing the feedback given by @200_success. The previous one (A faster way to compute the largest prime factor) tested my patience, but still failed to give the ...
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### A faster way to compute the largest prime factor

I am self-learning js and came across this problem(#3) from the Euler Project The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143 ? ...
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### Create a town administration report

I am Learning Javascript, after doing Java development for 2 years. I am doing a module on udemy which had a coding challenge which I completed and it works but wanted to get it reviewed to find out ...
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### Sort Array By Parity

The task is taken from leetcode Given an array A of non-negative integers, return an array consisting of all the even elements of A, followed by all the odd elements of A. You may return any ...
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### TLE error: Remove element from LinkedList [closed]

I am working on an easy LinkedList basic operation problem on Remove Linked List Elements - LeetCode Remove Linked List Elements Remove all elements from a linked list of integers that ...
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### Prompting the user to input a data value into an element in a linked list

I'm working through a practice problem that is having me build and modify a linked list over a series of steps. I am particularly interested in knowing if there's a more elegant way of prompting the ...
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### N-Repeated Element in Size 2N Array

The task is taken from leetcode In a array A of size 2N, there are N+1 unique elements, and exactly one of these elements is repeated N times. Return the element repeated N times. ...
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### Items also occurs in a set

The task You're given strings J representing the types of stones that are jewels, and S representing the stones you have. Each character in S is a type of stone you have. You want to know how ...
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### New Year Chaos JavaScript, needs to be sped up

Similar to this question but this is for Python Original problem with description on hacker rank I am currently trying to iterate through a large number of arrays and count how many times numbers ...
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### Determine whether an integer is a palindrome

The task Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: ...
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### Segmented Sieve Spoj

I tried(trying...) to solve the SPOJ prime number problem PRIME1 so i learned and implemented Segmented Sieve correctly but this program works in time for 10^8 but getting Time limit exceeded (TLE) ...
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### LeetCode gas station implementation

There are N gas stations along a circular route, where the amount of gas at station i is gas[i]. You have a car with an unlimited gas tank and it costs cost[i] of gas to travel from station i ...
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### Determine whether there exists a one-to-one character mapping from one string to another

The task Determine whether there exists a one-to-one character mapping from one string s1 to another s2. For example, given s1 = abc and s2 = bcd, return true since we can map a to b, b to ...
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### Project Euler #5 in C++

I'm currently doing the Project Euler challenges to learn C++. The fifth problem is the following. 2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any ...
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### Find non-duplicated integer in a list where every integer occurs three times except for one integer

The task Given an array of integers where every integer occurs three times except for one integer, which only occurs once, find and return the non-duplicated integer. For example, given [6,...
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### Division without using division, multiplication, or modulus operators

The task Implement division of two positive integers without using the division, multiplication, or modulus operators. Return the quotient as an integer, ignoring the remainder. My solution <...