HackerRank-Solutions

HackerRank | Practice, Tutorials & Interview Preparation Solutions

This repository consists of solutions to HackerRank practice, tutorials, and interview preparation problems with Python, mySQL, C#, and JavaScript.

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Table Of Contents

• Practices Completed
• Tutorials Completed
• Interview Preparation Kit
• Certificates

Practices Completed

• Python
• Regex
• Security
• SQL

Python

Subdomain	Challenge	Problem	Difficulty	Score	Solution
Introduction	Say ‘Hello, World!’ With Python	Problem	Easy	5	Solution
Introduction	Python If-Else	Problem	Easy	10	Solution
Introduction	Arithmetic Operators	Problem	Easy	10	Solution
Introduction	Python Division	Problem	Easy	10	Solution
Introduction	Loops	Problem	Easy	10	Solution
Introduction	Write a function	Problem	Medium	10	Solution
Introduction	Print Function	Problem	Easy	20	Solution
Basic Data Types	List Comprehensions	Problem	Easy	10	Solution
Basic Data Types	Find the Runner-Up Score!	Problem	Easy	10	Solution
Basic Data Types	Nested Lists	Problem	Easy	10	Solution
Basic Data Types	Finding the percentage	Problem	Easy	10	Solution
Basic Data Types	Lists	Problem	Easy	10	Solution
Basic Data Types	Tuples	Problem	Easy	10	Solution
Strings	sWAP cASE	Problem	Easy	10	Solution
Strings	String Split and Join	Problem	Easy	10	Solution
Strings	What’s Your Name?	Problem	Easy	10	Solution
Strings	Mutations	Problem	Easy	10	Solution
Strings	Find a string	Problem	Easy	10	Solution
Strings	String Validators	Problem	Easy	10	Solution
Strings	Text Alignment	Problem	Easy	10	Solution
Strings	Text Wrap	Problem	Easy	10	Solution
Strings	Designer Door Mat	Problem	Easy	10	Solution
Strings	String Formatting	Problem	Easy	10	Solution
Strings	Alphabet Rangoli	Problem	Easy	20	Solution
Strings	Capitalize!	Problem	Easy	20	Solution
Strings	The Minion Game	Problem	Medium	40	Solution
Strings	Merge the Tools!	Problem	Medium	40	Solution
Sets	Introduction to Sets	Problem	Easy	10	Solution
Sets	No Idea!	Problem	Medium	50	Solution
Sets	Symmetric Difference	Problem	Easy	10	Solution
Sets	Set add()	Problem	Easy	10	Solution
Sets	Set discard() remove() pop()	Problem	Easy	10	Solution
Sets	Set union() Operation	Problem	Easy	10	Solution
Sets	Set intersection() Operation	Problem	Easy	10	Solution
Sets	Set difference() Operation	Problem	Easy	10	Solution
Sets	Set symmetric_difference() Operation	Problem	Easy	10	Solution
Sets	Set Mutations	Problem	Easy	10	Solution
Sets	The Captain’s Room	Problem	Easy	10	Solution
Sets	Check Subset	Problem	Easy	10	Solution
Sets	Check Strict Superset	Problem	Easy	10	Solution
Math	Polar Coordinates	Problem	Easy	10	Solution
Math	Find Angle MBC	Problem	Medium	10	Solution
Math	Triangle Quest 2	Problem	Medium	20	Solution
Math	Mod Divmod	Problem	Easy	10	Solution
Math	Power - Mod Power	Problem	Easy	10	Solution
Math	Integers Come In All Sizes	Problem	Easy	10	Solution
Math	Triangle Quest	Problem	Medium	20	Solution
Itertools	itertools.product()	Problem	Easy	10	Solution
Itertools	itertools.permutations()	Problem	Easy	10	Solution
Itertools	itertools.combinations()	Problem	Easy	10	Solution
Itertools	itertools.combinations_with_replacement()	Problem	Easy	10	Solution
Itertools	Compress the String!	Problem	Medium	20	Solution
Itertools	Iterables and Iterators	Problem	Medium	40	Solution
Itertools	Maximize It!	Problem	Hard	50	Solution
Collections	collections.Counter()	Problem	Easy	10	Solution
Collections	defaultdict Tutorial	Problem	Easy	20	Solution
Collections	collections.namedtuple()	Problem	Easy	20	Solution
Collections	collections.OrderedDict()	Problem	Easy	20	Solution
Collections	collections.deque()	Problem	Easy	20	Solution
Collections	Company Logo	Problem	Medium	40	Solution
Collections	Word Order	Problem	Medium	50	Solution
Collections	Piling Up!	Problem	Medium	50	Solution
Date and Time	Calendar Module	Problem	Easy	10	Solution
Date and Time	Time Delta	Problem	Medium	30	Solution
Errors and Exceptions	Exceptions	Problem	Easy	10	Solution
Errors and Exceptions	Incorrect Regex	Problem	Easy	20	Solution
Classes	Classes - Dealing with Complex Numbers	Problem	Medium	20	Solution
Classes	Class 2 - Find the Torsional Angle	Problem	Easy	20	Solution

Regex

Subdomain	Challenge	Problem	Difficulty	Score	Solution
Introduction	Matching Specific String	Problem	Easy	5	Solution
Introduction	Matching Anything But a Newline	Problem	Easy	5	Solution
Introduction	Matching Digits & Non-Digit Characters	Problem	Easy	5	Solution
Introduction	Matching Whitespace & Non-Whitespace Character	Problem	Easy	5	Solution
Introduction	Matching Word & Non-Word Character	Problem	Easy	5	Solution
Introduction	Matching Start & End	Problem	Easy	5	Solution
Character Class	Matching Specific Characters	Problem	Easy	10	Solution
Character Class	Excluding Specific Characters	Problem	Easy	10	Solution
Character Class	Matching Character Ranges	Problem	Easy	10	Solution
Repetitions	Matching {x} Repetitions	Problem	Easy	20	Solution
Repetitions	Matching {x, y} Repetitions	Problem	Easy	20	Solution
Repetitions	Matching Zero Or More Repetitions	Problem	Easy	20	Solution
Repetitions	Matching One Or More Repetitions	Problem	Easy	20	Solution
Repetitions	Matching Ending Items	Problem	Easy	20	Solution
Grouping and Capturing	Matching Word Boundaries	Problem	Easy	20	Solution
Grouping and Capturing	Capturing & Non-Capturing Groups	Problem	Easy	20	Solution
Grouping and Capturing	Alternative Matching	Problem	Easy	20	Solution
Backreferences	Matching Same Text Again & Again	Problem	Easy	20	Solution
Backreferences	Backreferences To Failed Groups	Problem	Easy	20	Solution
Backreferences	Branch Reset Groups	Problem	Easy	20	Solution
Backreferences	Forward References	Problem	Easy	20	Solution
Assertions	Positive Lookahead	Problem	Easy	20	Solution
Assertions	Negative Lookahead	Problem	Easy	20	Solution
Assertions	Positive Lookbehind	Problem	Easy	20	Solution
Assertions	Negative Lookbehind	Problem	Easy	20	Solution

Security

Subdomain	Challenge	Problem	Difficulty	Score	Solution
Functions	Security Functions	Problem	Easy	5	Solution
Functions	Security Functions II	Problem	Easy	5	Solution
Functions	Security Bijective Functions	Problem	Easy	10	Solution
Functions	Security Function Inverses	Problem	Easy	10	Solution
Functions	Security Permutations	Problem	Easy	10	Solution
Functions	Security Involution	Problem	Easy	10	Solution
Terminology and Concepts	Security - Message Space and Ciphertext Space	Problem	Easy	10	Solution
Terminology and Concepts	Security Key Spaces	Problem	Easy	10	Solution
Terminology and Concepts	Security Encryption Scheme	Problem	Easy	10	Solution
Cryptography	PRNG Sequence Guessing	Problem	Medium	50	Solution
Cryptography	Keyword Transposition Cipher	Problem	Easy	50	Solution
Cryptography	Basic Cryptanalysis	Problem	Hard	50	Solution

SQL

Subdomain	Challenge	Problem	Difficulty	Score	Solution
Basic Select	Reversing the Select Query I	Problem	Easy	10	Solution
Basic Select	Revising the Select Query II	Problem	Easy	10	Solution
Basic Select	Select All	Problem	Easy	10	Solution
Basic Select	Select By ID	Problem	Easy	10	Solution
Basic Select	Japanese Cities’ Attributes	Problem	Easy	10	Solution
Basic Select	Japanese Cities’ Names	Problem	Easy	10	Solution
Basic Select	Weather Observation Station 1	Problem	Easy	15	Solution
Basic Select	Weather Observation Station 3	Problem	Easy	10	Solution
Basic Select	Weather Observation Station 4	Problem	Easy	10	Solution
Basic Select	Weather Observation Station 5	Problem	Easy	30	Solution
Basic Select	Weather Observation Station 6	Problem	Easy	10	Solution
Basic Select	Weather Observation Station 7	Problem	Easy	10	Solution
Basic Select	Weather Observation Station 8	Problem	Easy	15	Solution
Basic Select	Weather Observation Station 9	Problem	Easy	10	Solution
Basic Select	Weather Observation Station 10	Problem	Easy	10	Solution
Basic Select	Weather Observation Station 11	Problem	Easy	15	Solution
Basic Select	Weather Observation Station 12	Problem	Easy	15	Solution
Basic Select	Higher Than 75 Marks	Problem	Easy	15	Solution
Basic Select	Employee Names	Problem	Easy	10	Solution
Basic Select	Employee Salaries	Problem	Easy	10	Solution
Advanced Select	Type of Triangle	Problem	Easy	20	Solution
Advanced Select	The PADS	Problem	Medium	30	Solution
Advanced Select	Occupations	Problem	Medium	30	Solution
Advanced Select	Binary Tree Nodes	Problem	Medium	30	Solution
Advanced Select	New Companies	Problem	Medium	30	Solution
Aggregation	Revising Aggregations - The Count Function	Problem	Easy	10	Solution
Aggregation	Revising Aggregations - The Sum Function	Problem	Easy	10	Solution
Aggregation	Revising Aggregations - Averages	Problem	Easy	10	Solution
Aggregation	Average Population	Problem	Easy	10	Solution
Aggregation	Japan Population	Problem	Easy	10	Solution
Aggregation	Population Density Difference	Problem	Easy	10	Solution
Aggregation	The Blunder	Problem	Easy	15	Solution
Aggregation	Top Earners	Problem	Easy	20	Solution
Aggregation	Weather Observation Station 2	Problem	Easy	15	Solution
Aggregation	Weather Observation Station 13	Problem	Easy	10	Solution
Aggregation	Weather Observation Station 14	Problem	Easy	10	Solution
Aggregation	Weather Observation Station 15	Problem	Easy	15	Solution
Aggregation	Weather Observation Station 16	Problem	Easy	10	Solution
Aggregation	Weather Observation Station 17	Problem	Easy	15	Solution
Aggregation	Weather Observation Station 18	Problem	Medium	25	Solution
Aggregation	Weather Observation Station 19	Problem	Medium	30	Solution
Aggregation	Weather Observation Station 20	Problem	Medium	40	Solution

Tutorials Completed

• 10 Days of JavaScript
• 10 Days of Statistics
• 30 Days of Code

10 Days of JavaScript

Day	Challenge	Problem	Difficulty	Score	Solution
0	Hello, World!	Problem	Easy	10	Solution
0	Data Types	Problem	Easy	10	Solution
1	Arithmetic Operators	Problem	Easy	10	Solution
1	Functions	Problem	Easy	10	Solution
1	Let and Const	Problem	Easy	10	Solution
2	Conditional Statements - If-Else	Problem	Easy	10	Solution
2	Conditional Statements - Switch	Problem	Easy	10	Solution
2	Loops	Problem	Easy	10	Solution
3	Arrays	Problem	Easy	15	Solution
3	Try, Catch, and Finally	Problem	Easy	15	Solution
3	Throw	Problem	Easy	15	Solution
4	Create a Rectangle Object	Problem	Easy	15	Solution
4	Count Objects	Problem	Easy	15	Solution
4	Classes	Problem	Easy	15	Solution
5	Inheritance	Problem	Easy	15	Solution
5	Template Literals	Problem	Easy	15	Solution
5	Arrow Functions	Problem	Easy	15	Solution
6	Bitwise Operators	Problem	Easy	15	Solution
6	JavaScript Dates	Problem	Easy	15	Solution
7	Regular Expressions I	Problem	Easy	15	Solution
7	Regular Expressions II	Problem	Easy	15	Solution
7	Regular Expressions III	Problem	Easy	15	Solution
8	Create a Button	Problem	Easy	20	Solution
8	Buttons Container	Problem	Easy	25	Solution
9	Binary Calculator	Problem	Medium	30	Solution

10 Days of Statistics

Day	Challenge	Problem	Difficulty	Score	Solution
0	Mean, Median, and Mode	Problem	Easy	30	Solution
0	Weighted Mean	Problem	Easy	30	Solution
1	Quartiles	Problem	Easy	30	Solution
1	Interquartile Range	Problem	Easy	30	Solution
1	Standard Deviation	Problem	Easy	30	Solution
2	Basic Probability	Problem	Easy	10	Solution
2	More Dice	Problem	Easy	10	Solution
2	Compound Event Probability	Problem	Easy	10	Solution
3	Conditional Probability	Problem	Easy	10	Solution
3	Cards of the Same Suit	Problem	Easy	10	Solution
3	Drawing Marbles	Problem	Easy	10	Solution
4	Binomial Distribution I	Problem	Easy	30	Solution
4	Binomial Distribution II	Problem	Easy	30	Solution
4	Geometric Distribution I	Problem	Easy	30	Solution
4	Geometric Distribution II	Problem	Easy	30	Solution
5	Poisson Distribution I	Problem	Easy	30	Solution
5	Poisson Distribution II	Problem	Easy	30	Solution
5	Normal Distribution I	Problem	Easy	30	Solution
5	Normal Distribution II	Problem	Easy	30	Solution
6	The Central Limit Theorem I	Problem	Easy	30	Solution
6	The Central Limit Theorem II	Problem	Easy	30	Solution
6	The Central Limit Theorem III	Problem	Easy	30	Solution
7	Pearson Correlation Coefficient I	Problem	Easy	30	Solution
7	Spearman’s Rank Correlation Coefficient	Problem	Easy	30	Solution
8	Least Square Regression Line	Problem	Easy	30	Solution
8	Pearson Correlation Coefficient II	Problem

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