This repo contains solutions to the practice and challenges of HackerRank platform. Major programming languages I am familiar with are Python, PHP, and JavaScript. So wherever possible I will be adding snippets in all 3 languages. Below is the list of topics covered so far and their progress.

Tutorials: 10 Days of Javascript

SL No.	Day	Challenge	Solution
1	Day 0	Data Types	day-0-data-types.js
2	Day 0	Hello, World!	day-0-hello-world.js
3	Day 1	Arithmetic Operators	day-1-arithmetic-operators.js
4	Day 1	Functions	day-1-functions.js
5	Day 1	Let and Const	day-1-let-and-const.js
6	Day 2	Conditional Statements	day-2-conditional-statements-if-else.js
7	Day 2	Conditional Statements	day-2-conditional-statements-switch.js
8	Day 2	Loops	day-2-loops.js
9	Day 3	Arrays	day-3-arrays.js
10	Day 3	Throw	day-3-throw.js
11	Day 3	Try, Catch, and Finally	day-3-try-catch-and-finally.js
12	Day 4	Classes	day-4-classes.js
13	Day 4	Count Objects	day-4-count-objects.js
14	Day 4	Create a Rectangle Object	day-4-create-a-rectangle-object.js
15	Day 5	Arrow Functions	day-5-arrow-functions.js
16	Day 5	Inheritance	day-5-inheritance.js
17	Day 5	Template Literals	day-5-template-literals.js
18	Day 6	Bitwise Operators	day-6-bitwise-operators.js
19	Day 6	JavaScript Dates	day-6-javascript-dates.js
20	Day 7	Regular Expressions I	day-7-regular-expressions-i.js
21	Day 7	Regular Expressions II	day-7-regular-expressions-ii.js
22	Day 7	Regular Expressions III	day-7-regular-expressions-iii.js
23	Day 8	Day 8: Create a Button	index.html
24	Day 8	Day 8: Buttons Container	index.html
25	Day 9	Day 9: Binary Calculator	index.html

Practice: Python (8%)

SL No.	Sub Module	Challenge	Solution
1	Introduction	Say "Hello, World!" With Python	py-hello-world.py
2	Introduction	Python If-Else	py-if-else.py
3	Introduction	Arithmetic Operators	python-arithmetic-operators.py
4	Introduction	Python: Division	python-division.py
5	Introduction	Python: Loops	python-loops.py
6	Introduction	Print Function	python-print.py
7	Introduction	Write a function	write-a-function.py
8	Basic data types	Find the Runner-Up Score!	find-second-maximum-number-in-a-list.py
9	Basic data types	Finding the percentage	finding-the-percentage.py
10	Basic data types	List Comprehensions	list-comprehensions.py
11	Basic data types	Nested Lists	nested-list.py
12	Basic data types	Lists	python-lists.py
13	Basic data types	Tuples	python-tuples.py
14	Strings	Find a string	find-a-string.py
15	Strings	Mutations	python-mutations.py
16	Strings	String Split and Join	python-string-split-and-join.py
17	Strings	String Validators	string-validators.py
18	Strings	sWAP cASE	swap-case.py
19	Strings	Text Alignment	text-alignment.py
20	Strings	What's Your Name?	whats-your-name.py

• [Strings]
• [Sets]
• [Math]
• [Itertools]
• [Collections]
• [Date and Time]
• [Errors and Exceptions]
• [Classes]
• [Built-Ins]
• [Python Functionals]
• [Regex and Parsing]
• [XML]
• [Closures and Decorators]
• [Numpy]
• [Debugging]

SQL

SL No.	Sub module	Challenge	Solution
1	Basic select	Employee Names	employee-names.mysql.sql
2	Basic select	Weather Observation Station 11	weather-observation-station-11.mysql.sql
3	Basic select	Weather Observation Station 8	weather-observation-station-8.mysql.sql
4	Basic select	Weather Observation Station 7	weather-observation-station-7.mysql.sql
5	Basic select	Weather Observation Station 6	weather-observation-station-6.mysql.sql
6	Basic select	Weather Observation Station 5	weather-observation-station-5.mysql.sql
7	Basic select	Weather Observation Station 4	weather-observation-station-4.mysql.sql
8	Basic select	Weather Observation Station 3	weather-observation-station-3.mysql.sql
9	Basic select	Weather Observation Station 12	weather-observation-station-12.mysql.sql
10	Basic select	Weather Observation Station 10	weather-observation-station-10.mysql.sql
11	Basic select	Higher Than 75 Marks	higher-than-75-marks.mysql.sql
12	Basic select	Weather Observation Station 1	weather-observation-station-1.mysql.sql
13	Basic select	Select By ID	select-by-id.mysql.sql
14	Basic select	Select All	select-all.mysql.sql
15	Basic select	Employee Salaries	salary-of-employees.mysql.sql
16	Basic select	Revising the Select Query II	revising-the-select-query-ii.mysql.sql
17	Basic select	Revising the Select Query I	revising-the-select-query-i.mysql.sql
18	Basic select	Japanese Cities' Names	japanese-cities-names.mysql.sql
19	Basic select	Japanese Cities' Attributes	japanese-cities-attributes.mysql.sql
20	Basic select	Weather Observation Station 9	weather-observation-station-9.mysql.sql
21	Advanced select	Occupations	occupations.mysql.sql
22	Advanced select	The PADS	the-pads.mysql.sql
23	Advanced select	Type of Triangle	what-type-of-triangle.mysql.sql
24	Advanced select	Binary Tree Nodes	binary-search-tree-1.sql
25	Advanced select	New Companies	the-company.sql
26	Aggregation	Average Population	average-population.mysql.sql
27	Aggregation	Weather Observation Station 14	weather-observation-station-14.mysql.sql
28	Aggregation	Weather Observation Station 2	weather-observation-station-2.mysql.sql
29	Aggregation	Weather Observation Station 18	weather-observation-station-18.mysql.sql
30	Aggregation	Weather Observation Station 17	weather-observation-station-17.mysql.sql
31	Aggregation	Weather Observation Station 16	weather-observation-station-16.mysql.sql
32	Aggregation	Weather Observation Station 15	weather-observation-station-15.mysql.sql
33	Aggregation	Weather Observation Station 13	weather-observation-station-13.mysql.sql
34	Aggregation	Top Earners	earnings-of-employees.mysql.sql
35	Aggregation	The Blunder	the-blunder.mysql.sql
36	Aggregation	Revising Aggregations - The Count Function	revising-aggregations-the-count-function.mysql.sql
37	Aggregation	Revising Aggregations - Averages	revising-aggregations-the-average-function.mysql.sql
38	Aggregation	Revising Aggregations - The Sum Function	revising-aggregations-sum.mysql.sql
39	Aggregation	Population Density Difference	population-density-difference.mysql.sql
40	Aggregation	Japan Population	japan-population.mysql.sql
41	Aggregation	Weather Observation Station 19	weather-observation-station-19.mysql.sql
42	Aggregation	Weather Observation Station 20	weather-observation-station-20.mysql.sql
43	Basic join	African Cities	african-cities.mysql.sql
44	Basic join	Asian Population	asian-population.mysql.sql
45	Basic join	Average Population of Each Continent	average-population-of-each-continent.mysql.sql
46	Basic join	The Report	the-report.mysql.sql
47	Basic join	Top Competitors	full-score.mysql.sql
48	Basic join	Ollivander's Inventory	ollivanders-inventory.mysql.sql
49	Basic join	Challenges	challenges.mysql.sql
50	Basic join	Contest Leaderboard	contest-leaderboard.mysql.sql
51	Advanced join	SQL Project Planning	sql-projects.mysql.sql
52	Advanced join	Placements	placements.mysql.sql
53	Advanced join	Symmetric Pairs	symmetric-pairs.mysql.sql
54	Advanced join	Interviews	interviews.mysql.sql
55	Advanced join	15 Days of Learning SQL	15-days-of-learning-sql.mysql.sql
56	Alternative queries	Draw The Triangle 1	draw-the-triangle-1.mysql.sql
57	Alternative queries	Draw The Triangle 2	draw-the-triangle-2.mysql.sql
58	Alternative queries	Print Prime Numbers	print-prime-numbers.mysql.sql

Regex (53%)

• Introduction
• Character Class
• Repetitions
• Grouping and Capturing
• Backreferences
• Assertions
• [Applications]