A collection of solutions and explanations of Hackerrank.com problems in many languages.
Solved problems of HackerRank. www.hackerrank.com
To see every contributors, please reference at here.
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 | ✓ | ||
| Minimum Swaps 2 | ✓ |
Techniques/Concepts
| Problem | Python3 | C++ | PHP |
|---|---|---|---|
| Time Complexity: Primality | ✓ | ||
| Recursion: Fibonacci Numbers | ✓ | ||
| Recursion: Davis' Staircase | ✓ | ||
| DP: Coin Change | ✓ | ||
| Bit Manipulation: Lonely Integer | ✓ |
https://www.hackerrank.com/contests/code-and-the-curious/challenges
| Problem | Python3 | C++ | PHP |
|---|---|---|---|
| Sell Statistics Query System | ✓ |
| Problem | Python3 | C++ | PHP |
|---|---|---|---|
| The Average Rating of Top Employees | ✓ | ||
| Simple Language | ✓ |
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 | Go |
|---|---|---|---|---|
| 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 | ✓ |
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 | ✓ |
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 | ✓ |
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 | ✓ |