Solutions to Hackerrank practice problems

This repository contains 173 solutions to Hackerrank practice problems with Python 3 and Oracle SQL.

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• Algorithms
  1. Warmup
     • Solve Me First | Problem | Solution | Score: 1
     • Simple Array Sum | Problem | Solution | Score: 10
     • Compare the Triplets | Problem | Solution | Score: 10
     • A Very Big Sum | Problem | Solution | Score: 10
     • Diagonal Difference | Problem | Solution | Score: 10
     • Plus Minus | Problem | Solution | Score: 10
     • Staircase | Problem | Solution | Score: 10
     • Mini-Max Sum | Problem | Solution | Score: 10
     • Birthday Cake Candles | Problem | Solution | Score: 10
     • Time Conversion | Problem | Solution | Score: 15
  2. Implementation
     • Grading Students | Problem | Solution | Score: 10
     • Apple and Orange | Problem | Solution | Score: 10
     • Kangaroo | Problem | Solution | Score: 10
     • Between Two Sets | Problem | Solution | Score: 10
     • Breaking the Records | Problem | Solution | Score: 10
     • Birthday Chocolate | Problem | Solution | Score: 10
     • Electronics Shop | Problem | Solution | Score: 15
     • Cats and a Mouse | Problem | Solution | Score: 15
     • Forming a Magic Square | Problem | Solution | Score: 20
     • Picking Numbers | Problem | Solution | Score: 20
     • Climbing the Leaderboard | Problem | Solution | Score: 20
     • The Hurdle Race | Problem | Solution | Score: 15
  3. Sorting
     • Intro to Tutorial Challenges | Problem | Solution | Score: 30
     • Big Sorting | Problem | Solution | Score: 20
  4. Search
     • Pairs | Problem | Solution | Score: 50
  5. Greedy
     • Minimum Absolute Difference in an Array | Problem | Solution | Score: 15
     • Marc's Cakewalk | Problem | Solution | Score: 15
     • Permuting Two Arrays | Problem | Solution | Score: 40
  6. Dynamic Programming
     • The Coin Change Problem | Problem | Solution | Score: 60
     • Equal | Problem | Solution | Score: 30
     • Sherlock and Cost | Problem | Solution | Score: 50
     • Construct the Array | Problem | Solution | Score: 35
     • Fibonacci Modified | Problem | Solution | Score: 45
• Artificial Intelligence Statistics and Machine Learning - Laptop Battery Life | Problem | Solution | Score: 10
• Data Structures
  1. Arrays
     • Arrays - DS | Problem | Solution | Score: 10
• Interview Preparation Kit
  1. Warm-up Challenges
     • Sock Merchant | Problem | Solution | Score: 10
     • Counting Valleys | Problem | Solution | Score: 15
     • Jumping on the Clouds | Problem | Solution | Score: 20
     • Repeated String | Problem | Solution | Score: 20
  2. Arrays
     • Arrays - Left Rotation | Problem | Solution | Score: 20
     • 2D Array - DS | Problem | Solution | Score: 15
     • New Year Chaos | Problem | Solution | Score: 40
     • Minimum Swaps 2 | Problem | Solution | Score: 40
     • Array Manipulation | Problem | Solution | Score: 60
  3. Dictionaries and Hashmaps
     • Hash Tables - Ransom Note | Problem | Solution | Score: 25
     • Two Strings | Problem | Solution | Score: 25
     • Count Triplets | Problem | Solution | Score: 25
     • Frequency Queries | Problem | Solution | Score: 40
     • Sherlock and Anagrams | Problem | Solution | Score: 50
  4. Sorting
     • Sorting - Bubble Sort | Problem | Solution | Score: 30
     • Mark and Toys | Problem | Solution | Score: 35
  5. Search
     • Hash Tables - Ice Cream Parlor | Problem | Solution | Score: 35
     • Minimum Time Required | Problem | Solution | Score: 35
     • Triple sum | Problem | Solution | Score: 40
  6. Dynamic Programming
     • Max Array Sum | Problem | Solution | Score: 20
• Python
  1. Introduction
     • Say Hello, World! With Python | Problem | Solution | Score: 5
     • Python If-Else | Problem | Solution | Score: 10
     • Arithmetic Operators | Problem | Solution | Score: 10
     • Python Division | Problem | Solution | Score: 10
     • Loops | Problem | Solution | Score: 10
     • Write a function | Problem | Solution | Score: 10
     • Print Function | Problem | Solution | Score: 20
  2. Basic Data Types
     • List Comprehensions | Problem | Solution | Score: 10
     • Find the Runner-Up Score! | Problem | Solution | Score: 10
     • Nested Lists | Problem | Solution | Score: 10
     • Finding the percentage | Problem | Solution | Score: 10
     • Lists | Problem | Solution | Score: 10
     • Tuples | Problem | Solution | Score: 10
  3. Strings
     • sWAP cASE | Problem | Solution | Score: 10
     • String Split and Join | Problem | Solution | Score: 10
     • What's Your Name | Problem | Solution | Score: 10
     • Mutations | Problem | Solution | Score: 10
     • Find a string | Problem | Solution | Score: 10
     • String Validators | Problem | Solution | Score: 10
     • Text Alignment | Problem | Solution | Score: 10
     • Text Wrap | Problem | Solution | Score: 10
     • Designer Door Mat | Problem | Solution | Score: 10
     • String Formatting | Problem | Solution | Score: 10
     • Capitalize! | Problem | Solution | Score: 20
  4. Sets
     • Introduction to Sets | Problem | Solution | Score: 10
     • No Idea! | Problem | Solution | Score: 50
     • Symmetric Difference | Problem | Solution | Score: 10
     • Set add() | Problem | Solution | Score: 10
     • Set discard() remove() pop() | Problem | Solution | Score: 10
     • Set union() Operation | Problem | Solution | Score: 10
     • Set intersection() Operation | Problem | Solution | Score: 10
     • Set difference() Operation | Problem | Solution | Score: 10
     • Set symmetric_difference() Operation | Problem | Solution | Score: 10
     • Set Mutations | Problem | Solution | Score: 10
     • The Captain's Room | Problem | Solution | Score: 10
     • Check Subset | Problem | Solution | Score: 10
     • Check Strict Superset | Problem | Solution | Score: 10
  5. Itertools
     • itertoolsproduct() | Problem | Solution | Score: 10
     • itertoolscombinations() | Problem | Solution | Score: 10
     • itertoolspermutations() | Problem | Solution | Score: 10
     • itertoolscombinations_with_replacement() | Problem | Solution | Score: 10
     • Compress the String! | Problem | Solution | Score: 20
     • Iterables and Iterators | Problem | Solution | Score: 40
     • Maximize It! | Problem | Solution | Score: 50
  6. Collections
     • collectionsCounter() | Problem | Solution | Score: 10
     • DefaultDict Tutorial | Problem | Solution | Score: 20
     • Collections namedtuple() | Problem | Solution | Score: 20
     • Collections OrderedDict() | Problem | Solution | Score: 20
     • Word Order | Problem | Solution | Score: 50
     • Collections deque() | Problem | Solution | Score: 20
     • Company Logo | Problem | Solution | Score: 30
     • Piling Up! | Problem | Solution | Score: 50
  7. Date and Time
     • Calendar Module | Problem | Solution | Score: 10
     • Time Delta | Problem | Solution | Score: 30
  8. Errors and Exceptions
     • Exceptions | Problem | Solution | Score: 10
     • Incorrect Regex | Problem | Solution | Score: 20
  9. Numpy
     • Arrays | Problem | Solution | Score: 10
     • Shape and Reshape | Problem | Solution | Score: 20
• SQL
  1. Basic Select
     • Revising the Select Query I | Problem | Solution | Score: 10
     • Revising the Select Query II | Problem | Solution | Score: 10
     • Select All | Problem | Solution | Score: 10
     • Select By ID | Problem | Solution | Score: 10
     • Japanese Cities' Attributes | Problem | Solution | Score: 10
     • Japanese Cities' Names | Problem | Solution | Score: 10
     • Weather Observation Station 1 | Problem | Solution | Score: 15
     • Weather Observation Station 3 | Problem | Solution | Score: 10
     • Weather Observation Station 4 | Problem | Solution | Score: 10
     • Weather Observation Station 5 | Problem | Solution | Score: 30
     • Weather Observation Station 6 | Problem | Solution | Score: 10
     • Weather Observation Station 7 | Problem | Solution | Score: 10
     • Weather Observation Station 8 | Problem | Solution | Score: 15
     • Weather Observation Station 9 | Problem | Solution | Score: 10
     • Weather Observation Station 10 | Problem | Solution | Score: 10
     • Weather Observation Station 11 | Problem | Solution | Score: 15
     • Weather Observation Station 12 | Problem | Solution | Score: 15
     • Higher Than 75 Marks | Problem | Solution | Score: 15
     • Employee Names | Problem | Solution | Score: 10
     • Employee Salaries | Problem | Solution | Score: 10
  2. Advanced Select
     • Type of Triangle | Problem | Solution | Score: 20
     • The PADS | Problem | Solution | Score: 30
     • Binary Tree Nodes | Problem | Solution | Score: 30
  3. Aggregation
     • Revising Aggregations - The Count Function | Problem | Solution | Score: 10
     • Revising Aggregations - The Sum Function | Problem | Solution | Score: 10
     • Revising Aggregations - Averages | Problem | Solution | Score: 10
     • Average Population | Problem | Solution | Score: 10
     • Japan Population | Problem | Solution | Score: 10
     • Population Density Difference | Problem | Solution | Score: 10
     • The Blunder | Problem | Solution | Score: 15
     • Top Earners | Problem | Solution | Score: 20
     • Weather Observation Station 2 | Problem | Solution | Score: 15
     • Weather Observation Station 13 | Problem | Solution | Score: 10
     • Weather Observation Station 14 | Problem | Solution | Score: 10
     • Weather Observation Station 15 | Problem | Solution | Score: 15
     • Weather Observation Station 16 | Problem | Solution | Score: 10
     • Weather Observation Station 17 | Problem | Solution | Score: 15
     • Weather Observation Station 18 | Problem | Solution | Score: 25
     • Weather Observation Station 19 | Problem | Solution | Score: 30
     • Weather Observation Station 20 | Problem | Solution | Score: 40
  4. Basic Join
     • Asian Population | Problem | Solution | Score: 10
     • African Cities | Problem | Solution | Score: 10
     • Average Population of Each Continent | Problem | Solution | Score: 10
     • The Report | Problem | Solution | Score: 20
• Tutorials
  1. 10 Days of Statistics
     • Day 0 - Mean, Median, and Mode | Problem | Solution | Score: 30
     • Day 0 - Weighted Mean | Problem | Solution | Score: 30
     • Day 1 - Quartiles | Problem | Solution | Score: 30
     • Day 1 - Interquartile Range | Problem | Solution | Score: 30
     • Day 1 - Standard Deviation | Problem | Solution | Score: 30
     • Day 4 - Binomial Distribution I | Problem | Solution | Score: 30
     • Day 4 - Binomial Distribution II | Problem | Solution | Score: 30
     • Day 4 - Geometric Distribution I | Problem | Solution | Score: 30
     • Day 4 - Geometric Distribution II | Problem | Solution | Score: 30
     • Day 5 - Poisson Distribution I | Problem | Solution | Score: 30
     • Day 5 - Poisson Distribution II | Problem | Solution | Score: 30
     • Day 5 - Normal Distribution I | Problem | Solution | Score: 30
     • Day 5 - Normal Distribution II | Problem | Solution | Score: 30
     • Day 6 - The Central Limit Theorem I | Problem | Solution | Score: 30
     • Day 6 - The Central Limit Theorem II | Problem | Solution | Score: 30
     • Day 6 - The Central Limit Theorem III | Problem | Solution | Score: 30