HackerRank

A collection of solutions and explanations of Hackerrank.com problems in many languages.

Solved problems of HackerRank. www.hackerrank.com

Contributions

To see every contributors, please reference at here.

Solutions

Cracking the Coding Interview (DEPRECATED)

https://www.hackerrank.com/domains/tutorials/cracking-the-coding-interview

Data Structures

Problem	Python3	C++	PHP
Arrays: Left Rotation	✓	✓
Strings: Making Anagrams	✓
Hash Tables: Ransom Note	✓
Linked Lists: Detect a Cycle	✓
Stacks: Balanced Brackets	✓
Queues: A Tale of Two Stacks	✓
Tries: Contacts	✓

Algorithms

Problem	Python3	C++	PHP
Sorting: Bubble Sort	✓
Sorting: Comparator	✓
Hash Tables: Ice Cream Parlor	✓
DFS: Connected Cell in a Grid	✓

Techniques/Concepts

Problem	Python3	C++	PHP
Time Complexity: Primality	✓
Recursion: Fibonacci Numbers	✓
Recursion: Davis' Staircase	✓
DP: Coin Change	✓
Bit Manipulation: Lonely Integer	✓

Contest: OLX - Code and the Curious

https://www.hackerrank.com/contests/code-and-the-curious/challenges

Problem	Python3	C++	PHP
Sell Statistics Query System	✓

Contest: Week of Code 37

Problem	Python3	C++	PHP
The Average Rating of Top Employees		✓
Simple Language	✓

Algorithms

Warmup

Problem	Python3	C++	PHP
Solve Me First	✓	✓
Simple Array Sum	✓	✓
Compare the Triplets	✓	✓
A Very Big Sum	✓	✓
Diagonal Difference		✓
Plus Minus	✓	✓
Staircase	✓	✓
Mini-Max Sum		✓	✓
Birthday Cake Candles		✓	✓
Time Conversion	✓	✓	✓

Implementation

Problem	Python3	C++	PHP
Grading Students	✓	✓
Apple and Orange		✓
Kangaroo		✓
Between Two Sets		✓
Breaking the Records		✓
Birthday Chocolate		✓
Divisible Sum Pairs			✓
Migratory Birds			✓
Day of the Programmer	✓
Bon Appétit			✓
Sock Merchant			✓
Drawing Book			✓
Counting Valleys	✓
Electronics Shop	✓
Cats and a Mouse	✓
Picking Numbers			✓
Climbing the Leaderboard	✓
The Hurdle Race			✓
Designer PDF Viewer			✓
Utopian Tree			✓
Jumping on the Clouds: Revisited	✓
Find Digits	✓
Extra Long Factorials	✓
Jumping on the Clouds			✓
Minimum Distances			✓
The Grid Search		✓
Absolute Permutation		✓

Strings

Problem	Python3	C++	PHP
Super Reduced String			✓
CamelCase	✓		✓
Strong Password	✓
Two Characters			✓
Caesar Cipher			✓
Mars Exploration			✓
HackerRank in a String!	✓
Pangrams	✓		✓
Alternating Characters	✓
String Construction			✓
Ashton and String		✓
Two Strings			✓

Sorting

Problem	Python3	C++	PHP
Big Sorting			✓
Intro to Tutorial Challenges			✓
Insertion Sort - Part 1			✓
Counting Sort 1			✓

Searching

Problem	Python3	C++	PHP
Ice Cream Parlor			✓

Graph Theory

Problem	Python3	C++	PHP
Journey to the Moon	✓

Greedy

Problem	Python3	C++	PHP
Marc's Cakewalk			✓

Dynamic Programming

Problem	Python3	C++	PHP
The Maximum Subarray		✓

Bit Manipulation

Problem	Python3	C++	PHP
Lonely Integer			✓
Maximizing XOR			✓
Flipping bits			✓

Data Structures

Arrays

Problem	Python3	C++	PHP
Arrays - DS			✓
2D Array - DS			✓
Left Rotation	✓
Is This a Binary Search Tree?	✓

Linked Lists

Problem	Python3	C++	PHP
Reverse a doubly linked list		✓

Functional Programming

Introduction

Problem	Clojure
Solve Me First FP	✓
Hello World	✓
Hello World N Times	✓
List Replication	✓
Filter Array	✓
Filter Positions in a List	✓
Array Of N Elements	✓
Reverse a List	✓
Sum of Odd Elements	✓
List Length	✓
Update List	✓
Evaluating e^x	✓

SQL

Basic Select

Problem	MySQL
Revising the Select Query I	✓
Revising the Select Query II	✓
Select All	✓
Select By ID	✓
Japanese Cities' Attributes	✓
Japanese Cities' Names	✓
Weather Observation Station 1	✓
Weather Observation Station 3	✓
Weather Observation Station 4	✓
Weather Observation Station 5	✓
Weather Observation Station 6	✓
Weather Observation Station 7	✓
Weather Observation Station 8	✓
Weather Observation Station 9	✓
Weather Observation Station 10	✓
Weather Observation Station 11	✓
Weather Observation Station 12	✓
Higher Than 75 Marks	✓
Employee Names	✓
Employee Salaries	✓