https://github.com/gnodivad/hackerrank_solutions
My solutions to HackerRank practice problems
https://github.com/gnodivad/hackerrank_solutions
hackerrank-solutions hackkerrank java mysql
Last synced: 2 months ago
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My solutions to HackerRank practice problems
- Host: GitHub
- URL: https://github.com/gnodivad/hackerrank_solutions
- Owner: gnodivad
- Created: 2019-01-03T03:17:15.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2020-03-25T01:06:57.000Z (over 6 years ago)
- Last Synced: 2025-03-14T09:14:31.527Z (over 1 year ago)
- Topics: hackerrank-solutions, hackkerrank, java, mysql
- Language: Java
- Homepage:
- Size: 211 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
Awesome Lists containing this project
README
# 30 Days of Code
| Day | Challenge | Difficulty | Points | Solution |
|:---:|:--------------------------------------------------------------------------------------------------:|:----------:|:------:|:-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------:|
| 0 | [Hello, World](https://www.hackerrank.com/challenges/30-hello-world) | Easy | 30 | [
](30%20Days%20Of%20Code/Day00%20-%20Hello,%20World/Day00.js) [
](30%20Days%20Of%20Code/Day00%20-%20Hello,%20World/Day00.java) |
| 1 | [Data Types](https://www.hackerrank.com/challenges/30-data-types) | Easy | 30 | [](30%20Days%20Of%20Code/Day01%20-%20Data%20Types/Day01.js) [](30%20Days%20Of%20Code/Day01%20-%20Data%20Types/Day01.java) |
| 2 | [Operators](https://www.hackerrank.com/challenges/30-operators) | Easy | 30 | [](30%20Days%20Of%20Code/Day02%20-%20Operators/Day02.js) [](30%20Days%20Of%20Code/Day02%20-%20Operators/Day02.java) |
| 3 | [Intro to Conditional Statements](https://www.hackerrank.com/challenges/30-conditional-statements) | Easy | 30 | [](30%20Days%20Of%20Code/Day03%20-%20Intro%20to%20Conditional%20Statements/Day03.js) [](30%20Days%20Of%20Code/Day03%20-%20Intro%20to%20Conditional%20Statements/Day03.java) |
| 4 | [Class vs. Instance](https://www.hackerrank.com/challenges/30-class-vs-instance) | Easy | 30 | [](30%20Days%20Of%20Code/Day04%20-%20Class%20vs.%20Instance/Day04.js) [](30%20Days%20Of%20Code/Day04%20-%20Class%20vs.%20Instance/Day04.java) |
| 5 | [Loops](https://www.hackerrank.com/challenges/30-loops) | Easy | 30 | [](30%20Days%20Of%20Code/Day05%20-%20Loops/Day05.js) [](30%20Days%20Of%20Code/Day05%20-%20Loops/Day05.java) |
| 6 | [Let's Review](https://www.hackerrank.com/challenges/30-review-loop) | Easy | 30 | [](30%20Days%20Of%20Code/Day06%20-%20Lets%20Review/Day06.js) [](30%20Days%20Of%20Code/Day06%20-%20Lets%20Review/Day06.java) |
# Interview Preparation Kit
| Subdomain | Challenge | Difficulty | Points | Solution |
|:-------------------:|:------------------------------------------------------------------------------------------------:|:----------:|:------:|:-------------------------------------------------------------------------------------------------------------------------:|
| Warm-up Challenges | [Sock Merchant](https://www.hackerrank.com/challenges/sock-merchant) | Easy | 10 | [](Interview%20Preparation%20Kit/Warm-up%20Challenges/sock-merchant.java) |
| Warm-up Challenges | [Counting Valleys](https://www.hackerrank.com/challenges/counting-valleys) | Easy | 15 | [](Interview%20Preparation%20Kit/Warm-up%20Challenges/counting-valleys.java) |
| Warm-up Challenges | [Jumping on the Clouds](https://www.hackerrank.com/challenges/jumping-on-the-clouds) | Easy | 20 | [](Interview%20Preparation%20Kit/Warm-up%20Challenges/jumping-on-the-clouds.java) |
| Warm-up Challenges | [Repeated String](https://www.hackerrank.com/challenges/repeated-string) | Easy | 20 | [](Interview%20Preparation%20Kit/Warm-up%20Challenges/repeated-string.java) |
| Arrays | [2D Array - DS](https://www.hackerrank.com/challenges/2d-array) | Easy | 15 | [](Interview%20Preparation%20Kit/Arrays/2d-array.java) |
| Arrays | [Arrays: Left Rotation](https://www.hackerrank.com/challenges/ctci-array-left-rotation) | Easy | 20 | [](Interview%20Preparation%20Kit/Arrays/ctci-array-left-rotation.java) |
| Arrays | [New Year Chaos](https://www.hackerrank.com/challenges/new-year-chaos) | Medium | 40 | [](Interview%20Preparation%20Kit/Arrays/new-year-chaos.java) |
| Arrays | [Minimum Swaps 2](https://www.hackerrank.com/challenges/minimum-swaps-2) | Medium | 40 | [](Interview%20Preparation%20Kit/Arrays/minimum-swaps-2.java) |
| Arrays | [Array Manipulation](https://www.hackerrank.com/challenges/crush) | Hard | 60 | [](Interview%20Preparation%20Kit/Arrays/array-manipularion.java) |
| String Manipulation | [Strings: Making Anagrams](https://www.hackerrank.com/challenges/ctci-making-anagrams) | Easy | 25 | [](Interview%20Preparation%20Kit/String%20Manipulation/making-anagrams.java) |
| String Manipulation | [Alternating Characters](https://www.hackerrank.com/challenges/alternating-characters) | Easy | 20 | [](Interview%20Preparation%20Kit/String%20Manipulation/alternating-characters.java) |
| String Manipulation | [Sherlock and the Valid String](https://www.hackerrank.com/challenges/sherlock-and-valid-string) | Medium | 35 | [](Interview%20Preparation%20Kit/String%20Manipulation/sherlock-and-valid-string.java) |
| String Manipulation | [Special String Again](https://www.hackerrank.com/challenges/special-palindrome-again) | Medium | 40 | [](Interview%20Preparation%20Kit/String%20Manipulation/special-palindrome-again.java) |
# Problem Solving
| Subdomain | Challenge | Difficulty | Points | Solution |
|:--------------:|:------------------------------------------------------------------------------------:|:----------:|:------:|:------------------------------------------------------------------------------------------------:|
| Warmup | [Solve Me First](https://www.hackerrank.com/challenges/solve-me-first) | Easy | 1 | [
](Problem%20Solving/Warmup/solve-me-first.md) |
| Warmup | [Simple Array Sum](https://www.hackerrank.com/challenges/simple-array-sum) | Easy | 10 | [](Problem%20Solving/Warmup/simple-array-sum.md) |
| Warmup | [Compare the Triplets](https://www.hackerrank.com/challenges/compare-the-triplets) | Easy | 10 | [](Problem%20Solving/Warmup/compare-the-triplets.md) |
| Warmup | [A Very Big Sum](https://www.hackerrank.com/challenges/a-very-big-sum) | Easy | 10 | [](Problem%20Solving/Warmup/a-very-big-sum.md) |
| Warmup | [Diagonal Difference](https://www.hackerrank.com/challenges/diagonal-difference) | Easy | 10 | [](Problem%20Solving/Warmup/diagonal-difference.md) |
| Warmup | [Plus Minus](https://www.hackerrank.com/challenges/plus-minus) | Easy | 10 | [](Problem%20Solving/Warmup/plus-minus.md) |
| Warmup | [Staircase](https://www.hackerrank.com/challenges/staircase) | Easy | 10 | [](Problem%20Solving/Warmup/staircase.md) |
| Warmup | [Mini-Max Sum](https://www.hackerrank.com/challenges/mini-max-sum) | Easy | 10 | [](Problem%20Solving/Warmup/mini-max-sum.md) |
| Warmup | [Birthday Cake Candles](https://www.hackerrank.com/challenges/birthday-cake-candles) | Easy | 10 | [](Problem%20Solving/Warmup/birthday-cake-candles.md) |
| Warmup | [Time Conversion](https://www.hackerrank.com/challenges/time-conversion) | Easy | 15 | [](Problem%20Solving/Warmup/time-conversion.md) |
| Implementation | [Grading Students](https://www.hackerrank.com/challenges/grading) | Easy | 10 | [](Problem%20Solving/Implementation/grading.md) |
| Implementation | [Apple and Orange](https://www.hackerrank.com/challenges/apple-and-orange) | Easy | 10 | [](Problem%20Solving/Implementation/apple-and-orange.md) |
| Implementation | [Kangaroo](https://www.hackerrank.com/challenges/kangaroo) | Easy | 10 | [](Problem%20Solving/Implementation/kangaroo.md) |
| Implementation | [Between Two Sets](https://www.hackerrank.com/challenges/between-two-sets) | Easy | 10 | [](Problem%20Solving/Implementation/between-two-sets.md) |
| Implementation | [Divisible Sum Pairs](https://www.hackerrank.com/challenges/divisible-sum-pairs) | Easy | 10 | [](Problem%20Solving/Implementation/divisible-sum-pairs.md) |
| Implementation | [Bon Appétit](https://www.hackerrank.com/challenges/bon-appetit) | Easy | 10 | [](Problem%20Solving/Implementation/bon-appetit.md) |
| Implementation | [Sock Merchant](https://www.hackerrank.com/challenges/sock-merchant) | Easy | 10 | [](Problem%20Solving/Implementation/sock-merchant.md) |
# Java
| Subdomain | Challenge | Difficulty | Points | Solution |
|:---------------------------:|:--------------------------------------------------------------------------------------------------------------:|:----------:|:------:|:-----------------------------------------------------------------------------------------------------------------------:|
| Introduction | [Welcome to Java!](https://www.hackerrank.com/challenges/welcome-to-java) | Easy | 3 | [](Java/Introduction/welcome-to-java.java) |
| Introduction | [Java Stdin and Stdout I](https://www.hackerrank.com/challenges/java-stdin-and-stdout-1) | Easy | 5 | [](Java/Introduction/java-stdin-and-stdout-1.java) |
| Introduction | [Java If-Else](https://www.hackerrank.com/challenges/java-if-else) | Easy | 10 | [](Java/Introduction/java-if-else.java) |
| Introduction | [Java Stdin and Stdout II](https://www.hackerrank.com/challenges/java-stdin-stdout) | Easy | 10 | [](Java/Introduction/java-stdin-stdout.java) |
| Introduction | [Java Loops I](https://www.hackerrank.com/challenges/java-loops-i) | Easy | 10 | [](Java/Introduction/java-loops-i.java) |
| Introduction | [Java Output Formatting](https://www.hackerrank.com/challenges/java-output-formatting) | Easy | 10 | [](Java/Introduction/java-output-formatting.java) |
| Introduction | [Java Loops II](https://www.hackerrank.com/challenges/java-loops) | Easy | 10 | [](Java/Introduction/java-loops.java) |
| Introduction | [Java Datatypes](https://www.hackerrank.com/challenges/java-datatypes) | Easy | 10 | [](Java/Introduction/java-datatypes.java) |
| Introduction | [Java End-of-file](https://www.hackerrank.com/challenges/java-end-of-file) | Easy | 10 | [](Java/Introduction/java-end-of-file.java) |
| Introduction | [Java Static Initializer Block](https://www.hackerrank.com/challenges/java-static-initializer-block) | Easy | 10 | [](Java/Introduction/java-static-initializer-block.java) |
| Introduction | [Java Int to String](https://www.hackerrank.com/challenges/java-int-to-string) | Easy | 10 | [](Java/Introduction/java-int-to-string.java) |
| Introduction | [Java Date and Time](https://www.hackerrank.com/challenges/java-date-and-time) | Easy | 15 | [](Java/Introduction/java-date-and-time.java) |
| Introduction | [Java Currency Formatter](https://www.hackerrank.com/challenges/java-currency-formatter) | Easy | 15 | [](Java/Introduction/java-currency-formatter.java) |
| Strings | [Java Strings Introduction](https://www.hackerrank.com/challenges/java-strings-introduction) | Easy | 5 | [](Java/Strings/java-strings-introduction.java) |
| Strings | [Java Substring](https://www.hackerrank.com/challenges/java-substring) | Easy | 5 | [](Java/Strings/java-substring.java) |
| Strings | [Java Substring Comparisons](https://www.hackerrank.com/challenges/java-string-compare) | Easy | 10 | [](Java/Strings/java-string-compare.java) |
| Strings | [Java Substring Comparisons](https://www.hackerrank.com/challenges/java-string-reverse) | Easy | 10 | [](Java/Strings/java-string-reverse.java) |
| Strings | [Java Anagrams](https://www.hackerrank.com/challenges/java-anagrams) | Easy | 10 | [](Java/Strings/java-anagrams.java) |
| Strings | [Java String Tokens](https://www.hackerrank.com/challenges/java-string-tokens) | Easy | 15 | [](Java/Strings/java-string-tokens.java) |
| Strings | [Pattern Syntax Checker](https://www.hackerrank.com/challenges/pattern-syntax-checker) | Easy | 20 | [](Java/Strings/pattern-syntax-checker.java) |
| Strings | [Java Regex](https://www.hackerrank.com/challenges/java-regex) | Medium | 25 | [](Java/Strings/java-regex.java) |
| Strings | [Java Regex 2 - Duplicate Words](https://www.hackerrank.com/challenges/duplicate-word) | Medium | 25 | [](Java/Strings/duplicate-word.java) |
| Strings | [Valid Username Regular Expression](https://www.hackerrank.com/challenges/valid-username-checker) | Easy | 20 | [](Java/Strings/valid-username-checker.java) |
| Strings | [Tag Content Extractor](https://www.hackerrank.com/challenges/tag-content-extractor) | Medium | 20 | [](Java/Strings/tag-content-extractor.java) |
| BigNumber | [Java Primality Test](https://www.hackerrank.com/challenges/java-primality-test) | Easy | 20 | [](Java/BigNumber/java-primality-test.java) |
| BigNumber | [Java BigInteger](https://www.hackerrank.com/challenges/java-biginteger) | Easy | 10 | [](Java/BigNumber/java-biginteger.java) |
| BigNumber | [Java BigDecimal](https://www.hackerrank.com/challenges/java-bigdecimal) | Medium | 20 | [](Java/BigNumber/java-bigdecimal.java) |
| Data Structures | [Java 1D Array](https://www.hackerrank.com/challenges/java-1d-array-introduction) | Easy | 5 | [](Java/Data%20Structures/java-1d-array-introduction.java) |
| Data Structures | [Java 2D Array](https://www.hackerrank.com/challenges/java-2d-array) | Easy | 10 | [](Java/Data%20Structures/java-2d-array.java) |
| Data Structures | [Java Subarray](https://www.hackerrank.com/challenges/java-negative-subarray) | Easy | 10 | [](Java/Data%20Structures/java-negative-subarray.java) |
| Data Structures | [Java Arraylist](https://www.hackerrank.com/challenges/java-arraylist) | Easy | 10 | [](Java/Data%20Structures/java-arraylist.java) |
| Data Structures | [Java 1D Array (Part 2)](https://www.hackerrank.com/challenges/java-1d-array) | Medium | 25 | [](Java/Data%20Structures/java-1d-array.java) |
| Data Structures | [Java List](https://www.hackerrank.com/challenges/java-list) | Easy | 15 | [](Java/Data%20Structures/java-list.java) |
| Data Structures | [Java Map](https://www.hackerrank.com/challenges/phone-book) | Easy | 10 | [](Java/Data%20Structures/phone-book.java) |
| Data Structures | [Java Hashset](https://www.hackerrank.com/challenges/java-hashset) | Easy | 10 | [](Java/Data%20Structures/java-hashset.java) |
| Data Structures | [Java Stack](https://www.hackerrank.com/challenges/java-stack) | Medium | 20 | [](Java/Data%20Structures/java-stack.java) |
| Data Structures | [Java Generics](https://www.hackerrank.com/challenges/java-generics) | Easy | 15 | [](Java/Data%20Structures/java-generics.java) |
| Data Structures | [Java Comparator](https://www.hackerrank.com/challenges/java-comparator) | Medium | 10 | [](Java/Data%20Structures/java-comparator.java) |
| Data Structures | [Java Sort](https://www.hackerrank.com/challenges/java-sort) | Easy | 10 | [](Java/Data%20Structures/java-sort.java) |
| Data Structures | [Java Deque](https://www.hackerrank.com/challenges/java-dequeue) | Medium | 20 | [](Java/Data%20Structures/java-dequeue.java) |
| Data Structures | [Java BitSet](https://www.hackerrank.com/challenges/java-bitset) | Easy | 20 | [](Java/Data%20Structures/java-bitset.java) |
| Data Structures | [Java Priority Queue](https://www.hackerrank.com/challenges/java-priority-queue) | Medium | 20 | [](Java/Data%20Structures/java-priority-queue.java) |
| Object Oriented Programming | [Java Inheritance I](https://www.hackerrank.com/challenges/java-inheritance-1) | Easy | 5 | [](Java/Object%20Oriented%20Programming/java-inheritance-1.java) |
| Object Oriented Programming | [Java Inheritance II](https://www.hackerrank.com/challenges/java-inheritance-2) | Easy | 10 | [](Java/Object%20Oriented%20Programming/java-inheritance-2.java) |
| Object Oriented Programming | [Java Abstract Class](https://www.hackerrank.com/challenges/java-abstract-class) | Easy | 10 | [](Java/Object%20Oriented%20Programming/java-abstract-class.java) |
| Object Oriented Programming | [Java Interface](https://www.hackerrank.com/challenges/java-interface) | Easy | 10 | [](Java/Object%20Oriented%20Programming/java-interface.java) |
| Object Oriented Programming | [Java Method Overriding](https://www.hackerrank.com/challenges/java-method-overriding) | Easy | 10 | [](Java/Object%20Oriented%20Programming/java-method-overriding.java) |
| Object Oriented Programming | [Java Method Overriding 2](https://www.hackerrank.com/challenges/java-method-overriding-2-super-keyword) | Easy | 10 | [](Java/Object%20Oriented%20Programming/java-method-overriding-2-super-keyword.java) |
| Object Oriented Programming | [Java Instanceof keyword](https://www.hackerrank.com/challenges/java-instanceof-keyword) | Easy | 10 | [](Java/Object%20Oriented%20Programming/java-instanceof-keyword.java) |
| Object Oriented Programming | [Java Iterator](https://www.hackerrank.com/challenges/java-iterator) | Easy | 15 | [](Java/Object%20Oriented%20Programming/java-iterator.java) |
| Exception Handling | [Java Exception Handling (Try-catch)](https://www.hackerrank.com/challenges/java-exception-handling-try-catch) | Easy | 10 | [](Java/Exception%20Handling/java-exception-handling-try-catch.java) |
| Exception Handling | [Java Exception Handling](https://www.hackerrank.com/challenges/java-exception-handling) | Easy | 15 | [](Java/Exception%20Handling/java-exception-handling.java) |
| Advanced | [Java Varargs - Simple Addition](https://www.hackerrank.com/challenges/simple-addition-varargs) | Easy | 15 | [](Java/Advanced/simple-addition-varargs.java) |
| Advanced | [Java Reflection - Attributes](https://www.hackerrank.com/challenges/java-reflection-attributes) | Easy | 15 | [](Java/Advanced/java-reflection-attributes.java) |
| Advanced | [Can You Access?](https://www.hackerrank.com/challenges/can-you-access) | Medium | 25 | [](Java/Advanced/can-you-access.java) |
| Advanced | [Prime Checker](https://www.hackerrank.com/challenges/prime-checker) | Medium | 25 | [](Java/Advanced/prime-checker.java) |
| Advanced | [Java Factory Pattern](https://www.hackerrank.com/challenges/java-factory) | Easy | 15 | [](Java/Advanced/java-factory.java) |
| Advanced | [Java Singleton Pattern](https://www.hackerrank.com/challenges/java-singleton) | Easy | 15 | [](Java/Advanced/java-singleton.java) |
# SQL
| Subdomain | Challenge | Difficulty | Points | Solution |
|:-------------------:|:--------------------------------------------------------------------------------------------------------------------:|:----------:|:------:|:------------------------------------------------------------------------------------------------------:|
| Basic Select | [Revising the Select Query I](https://www.hackerrank.com/challenges/revising-the-select-query) | Easy | 10 | [
](SQL/Basic%20Select/revising-the-select-query.sql) |
| Basic Select | [Revising the Select Query II](https://www.hackerrank.com/challenges/revising-the-select-query-2) | Easy | 10 | [](SQL/Basic%20Select/revising-the-select-query-2.sql) |
| Basic Select | [Select All](https://www.hackerrank.com/challenges/select-all-sql) | Easy | 10 | [](SQL/Basic%20Select/select-all.sql) |
| Basic Select | [Select By ID](https://www.hackerrank.com/challenges/select-by-id) | Easy | 10 | [](SQL/Basic%20Select/select-by-id.sql) |
| Basic Select | [Japanese Cities' Attributes](https://www.hackerrank.com/challenges/japanese-cities-attributes) | Easy | 10 | [](SQL/Basic%20Select/japanese-cities-attributes.sql) |
| Basic Select | [Japanese Cities' Names](https://www.hackerrank.com/challenges/japanese-cities-name) | Easy | 10 | [](SQL/Basic%20Select/japanese-cities-name.sql) |
| Basic Select | [Weather Observation Station 1](https://www.hackerrank.com/challenges/weather-observation-station-1) | Easy | 15 | [](SQL/Basic%20Select/weather-observation-station-1.sql) |
| Basic Select | [Weather Observation Station 3](https://www.hackerrank.com/challenges/weather-observation-station-3) | Easy | 10 | [](SQL/Basic%20Select/weather-observation-station-3.sql) |
| Basic Select | [Weather Observation Station 4](https://www.hackerrank.com/challenges/weather-observation-station-4) | Easy | 10 | [](SQL/Basic%20Select/weather-observation-station-4.sql) |
| Basic Select | [Weather Observation Station 5](https://www.hackerrank.com/challenges/weather-observation-station-5) | Easy | 30 | [](SQL/Basic%20Select/weather-observation-station-5.sql) |
| Basic Select | [Weather Observation Station 6](https://www.hackerrank.com/challenges/weather-observation-station-6) | Easy | 10 | [](SQL/Basic%20Select/weather-observation-station-6.sql) |
| Basic Select | [Weather Observation Station 7](https://www.hackerrank.com/challenges/weather-observation-station-7) | Easy | 10 | [](SQL/Basic%20Select/weather-observation-station-7.sql) |
| Basic Select | [Weather Observation Station 8](https://www.hackerrank.com/challenges/weather-observation-station-8) | Easy | 15 | [](SQL/Basic%20Select/weather-observation-station-8.sql) |
| Basic Select | [Weather Observation Station 9](https://www.hackerrank.com/challenges/weather-observation-station-9) | Easy | 10 | [](SQL/Basic%20Select/weather-observation-station-9.sql) |
| Basic Select | [Weather Observation Station 10](https://www.hackerrank.com/challenges/weather-observation-station-10) | Easy | 15 | [](SQL/Basic%20Select/weather-observation-station-10.sql) |
| Basic Select | [Weather Observation Station 11](https://www.hackerrank.com/challenges/weather-observation-station-11) | Easy | 15 | [](SQL/Basic%20Select/weather-observation-station-11.sql) |
| Basic Select | [Weather Observation Station 12](https://www.hackerrank.com/challenges/weather-observation-station-12) | Easy | 15 | [](SQL/Basic%20Select/weather-observation-station-12.sql) |
| Basic Select | [Higher Than 75 Marks](https://www.hackerrank.com/challenges/more-than-75-marks) | Easy | 15 | [](SQL/Basic%20Select/more-than-75-marks.sql) |
| Basic Select | [Employee Names](https://www.hackerrank.com/challenges/name-of-employees) | Easy | 10 | [](SQL/Basic%20Select/name-of-employees.sql) |
| Basic Select | [Employee Salaries](https://www.hackerrank.com/challenges/salary-of-employees) | Easy | 10 | [](SQL/Basic%20Select/salary-of-employees.sql) |
| Advanced Select | [Type of Triangle](https://www.hackerrank.com/challenges/what-type-of-triangle) | Easy | 20 | [](SQL/Advanced%20Select/what-type-of-triangle.sql) |
| Advanced Select | [The PADS](https://www.hackerrank.com/challenges/the-pads) | Medium | 30 | [](SQL/Advanced%20Select/the-pads.sql) |
| Advanced Select | [Occupations](https://www.hackerrank.com/challenges/occupations) | Medium | 30 | [](SQL/Advanced%20Select/occupations.sql) |
| Advanced Select | [Binary Tree Nodes](https://www.hackerrank.com/challenges/binary-search-tree-1) | Medium | 30 | [](SQL/Advanced%20Select/binary-search-tree-1.sql) |
| Advanced Select | [New Companies](https://www.hackerrank.com/challenges/the-company) | Medium | 30 | [](SQL/Advanced%20Select/the-company.sql) |
| Aggregation | [Revising Aggregations](https://www.hackerrank.com/challenges/revising-aggregations-the-count-function) | Easy | 10 | [](SQL/Aggregation/revising-aggregations-the-count-function.sql) |
| Aggregation | [Revising Aggregations](https://www.hackerrank.com/challenges/revising-aggregations-sum) | Easy | 10 | [](SQL/Aggregation/revising-aggregations-sum.sql) |
| Aggregation | [Revising Aggregations - Averages](https://www.hackerrank.com/challenges/revising-aggregations-the-average-function) | Easy | 10 | [](SQL/Aggregation/revising-aggregations-the-average-function.sql) |
| Aggregation | [Average Population](https://www.hackerrank.com/challenges/average-population) | Easy | 10 | [](SQL/Aggregation/average-population.sql) |
| Aggregation | [Japan Population](https://www.hackerrank.com/challenges/japan-population) | Easy | 10 | [](SQL/Aggregation/japan-population.sql) |
| Aggregation | [Population Density Difference](https://www.hackerrank.com/challenges/population-density-difference) | Easy | 10 | [](SQL/Aggregation/population-density-difference.sql) |
| Aggregation | [The Blunder](https://www.hackerrank.com/challenges/the-blunder) | Easy | 15 | [](SQL/Aggregation/the-blunder.sql) |
| Aggregation | [Top Earners](https://www.hackerrank.com/challenges/earnings-of-employees) | Easy | 20 | [](SQL/Aggregation/earnings-of-employees.sql) |
| Aggregation | [Weather Observation Station 2](https://www.hackerrank.com/challenges/weather-observation-station-2) | Easy | 15 | [](SQL/Aggregation/weather-observation-station-2.sql) |
| Aggregation | [Weather Observation Station 13](https://www.hackerrank.com/challenges/weather-observation-station-13) | Easy | 10 | [](SQL/Aggregation/weather-observation-station-13.sql) |
| Aggregation | [Weather Observation Station 14](https://www.hackerrank.com/challenges/weather-observation-station-14) | Easy | 10 | [](SQL/Aggregation/weather-observation-station-14.sql) |
| Aggregation | [Weather Observation Station 15](https://www.hackerrank.com/challenges/weather-observation-station-15) | Easy | 15 | [](SQL/Aggregation/weather-observation-station-15.sql) |
| Aggregation | [Weather Observation Station 16](https://www.hackerrank.com/challenges/weather-observation-station-16) | Easy | 10 | [](SQL/Aggregation/weather-observation-station-16.sql) |
| Aggregation | [Weather Observation Station 17](https://www.hackerrank.com/challenges/weather-observation-station-17) | Easy | 15 | [](SQL/Aggregation/weather-observation-station-17.sql) |
| Aggregation | [Weather Observation Station 18](https://www.hackerrank.com/challenges/weather-observation-station-18) | Medium | 25 | [](SQL/Aggregation/weather-observation-station-18.sql) |
| Aggregation | [Weather Observation Station 19](https://www.hackerrank.com/challenges/weather-observation-station-19) | Medium | 30 | [](SQL/Aggregation/weather-observation-station-19.sql) |
| Aggregation | [Weather Observation Station 20](https://www.hackerrank.com/challenges/weather-observation-station-20) | Medium | 40 | [](SQL/Aggregation/weather-observation-station-20.sql) |
| Basic Join | [Asian Population](https://www.hackerrank.com/challenges/asian-population) | Easy | 10 | [](SQL/Basic%20Join/asian-population.sql) |
| Basic Join | [African Cities](https://www.hackerrank.com/challenges/african-cities) | Easy | 10 | [](SQL/Basic%20Join/african-cities.sql) |
| Basic Join | [Average Population of Each Continent](https://www.hackerrank.com/challenges/average-population-of-each-continent) | Easy | 10 | [](SQL/Basic%20Join/average-population-of-each-continent.sql) |
| Basic Join | [The Report](https://www.hackerrank.com/challenges/the-report) | Medium | 20 | [](SQL/Basic%20Join/the-report.sql) |
| Basic Join | [Top Competitors](https://www.hackerrank.com/challenges/full-score) | Medium | 30 | [](SQL/Basic%20Join/full-score.sql) |
| Basic Join | [Ollivander's Inventory](https://www.hackerrank.com/challenges/harry-potter-and-wands) | Medium | 30 | [](SQL/Basic%20Join/harry-potter-and-wands.sql) |
| Basic Join | [Challenges](https://www.hackerrank.com/challenges/challenges) | Medium | 30 | [](SQL/Basic%20Join/challenges.sql) |
| Basic Join | [Contest Leaderboard](https://www.hackerrank.com/challenges/contest-leaderboard) | Medium | 30 | [](SQL/Basic%20Join/contest-leaderboard.sql) |
| Advanced Join | [Projects](https://www.hackerrank.com/challenges/projects) | Medium | 40 | [](SQL/Advanced%20Join/projects.sql) |
| Advanced Join | [Placements](https://www.hackerrank.com/challenges/placements) | Medium | 40 | [](SQL/Advanced%20Join/placements.sql) |
| Advanced Join | [Symmetric Pairs](https://www.hackerrank.com/challenges/symmetric-pairs) | Medium | 40 | [](SQL/Advanced%20Join/symmetric-pairs.sql) |
| Advanced Join | [Interviews](https://www.hackerrank.com/challenges/interviews) | Hard | 50 | [](SQL/Advanced%20Join/interviews.sql) |
| Advanced Join | [Interviews](https://www.hackerrank.com/challenges/interviews) | Hard | 50 | [](SQL/Advanced%20Join/interviews.sql) |
| Advanced Join | [15 Days of Learning SQL](https://www.hackerrank.com/challenges/15-days-of-learning-sql) | Hard | 50 | [](SQL/Advanced%20Join/15-days-of-learning-sql.sql) |
| Alternative Queries | [Draw The Triangle 1](https://www.hackerrank.com/challenges/draw-the-triangle-1) | Easy | 25 | [](SQL/Alternative%20Queries/draw-the-triangle-1.sql) |
| Alternative Queries | [Draw The Triangle 2](https://www.hackerrank.com/challenges/draw-the-triangle-2) | Easy | 25 | [](SQL/Alternative%20Queries/draw-the-triangle-2.sql) |
# Regex
| Subdomain | Challenge | Difficulty | Points | Solution |
|:----------------------:|:------------------------------------------------------------------------------------------------------------------------------------:|:----------:|:------:|:-----------------------------------------------------------------------------------------------------------:|
| Introduction | [Matching Specific String](https://www.hackerrank.com/challenges/matching-specific-string) | Easy | 5 | [](Regex/Introduction/matching-specific-string.java) |
| Introduction | [Matching Anything But a Newline](https://www.hackerrank.com/challenges/matching-anything-but-new-line) | Easy | 5 | [](Regex/Introduction/matching-anything-but-new-line.java) |
| Introduction | [Matching Digits & Non-Digit Characters](https://www.hackerrank.com/challenges/matching-digits-non-digit-character) | Easy | 5 | [](Regex/Introduction/matching-digits-non-digit-character.java) |
| Introduction | [Matching Whitespace & Non-Whitespace Character](https://www.hackerrank.com/challenges/matching-whitespace-non-whitespace-character) | Easy | 5 | [](Regex/Introduction/matching-whitespace-non-whitespace-character.java) |
| Introduction | [Matching Word & Non-Word Character](https://www.hackerrank.com/challenges/matching-word-non-word) | Easy | 5 | [](Regex/Introduction/matching-word-non-word.java) |
| Introduction | [Matching Start & End](https://www.hackerrank.com/challenges/matching-start-end) | Easy | 5 | [](Regex/Introduction/matching-start-end.java) |
| Character Class | [Matching Specific Characters](https://www.hackerrank.com/challenges/matching-specific-characters) | Easy | 10 | [](Regex/Character%20Class/matching-specific-characters.java) |
| Character Class | [Excluding Specific Characters](https://www.hackerrank.com/challenges/excluding-specific-characters) | Easy | 10 | [](Regex/Character%20Class/excluding-specific-characters.java) |
| Character Class | [Matching Character Ranges](https://www.hackerrank.com/challenges/matching-range-of-characters) | Easy | 10 | [](Regex/Character%20Class/matching-range-of-characters.java) |
| Repetitions | [Matching {x} Repetitions](https://www.hackerrank.com/challenges/matching-x-repetitions) | Easy | 20 | [](Regex/Repetitions/matching-x-repetitions.java) |
| Repetitions | [Matching {x, y} Repetitions](https://www.hackerrank.com/challenges/matching-x-y-repetitions) | Easy | 20 | [](Regex/Repetitions/matching-x-y-repetitions.java) |
| Repetitions | [Matching Zero Or More Repetitions](https://www.hackerrank.com/challenges/matching-zero-or-more-repetitions) | Easy | 20 | [](Regex/Repetitions/matching-zero-or-more-repetitions.java) |
| Repetitions | [Matching One Or More Repetitions](https://www.hackerrank.com/challenges/matching-one-or-more-repititions) | Easy | 20 | [](Regex/Repetitions/matching-one-or-more-repititions.java) |
| Repetitions | [Matching Ending Items](https://www.hackerrank.com/challenges/matching-ending-items) | Easy | 20 | [](Regex/Repetitions/matching-ending-items.java) |
| Grouping and Capturing | [Matching Word Boundaries](https://www.hackerrank.com/challenges/matching-word-boundaries) | Easy | 20 | [](Regex/Grouping%20and%20Capturing/matching-word-boundaries.java) |
| Grouping and Capturing | [Capturing & Non-Capturing Groups](https://www.hackerrank.com/challenges/capturing-non-capturing-groups) | Easy | 20 | [](Regex/Grouping%20and%20Capturing/capturing-non-capturing-groups.java) |
| Grouping and Capturing | [Alternative Matching](https://www.hackerrank.com/challenges/alternative-matching) | Easy | 20 | [](Regex/Grouping%20and%20Capturing/alternative-matching.java) |
| Backreferences | [Matching Same Text Again & Again](https://www.hackerrank.com/challenges/matching-same-text-again-again) | Easy | 20 | [](Regex/Backreferences/matching-same-text-again-again.java) |
| Backreferences | [Backreferences To Failed Groups](https://www.hackerrank.com/challenges/backreferences-to-failed-groups) | Easy | 20 | [](Regex/Backreferences/backreferences-to-failed-groups.java) |
| Backreferences | [Branch Reset Groups](https://www.hackerrank.com/challenges/branch-reset-groups) | Easy | 20 | [](Regex/Backreferences/branch-reset-groups.php) |
| Backreferences | [Forward References](https://www.hackerrank.com/challenges/forward-references) | Easy | 20 | [](Regex/Backreferences/forward-references.java) |
| Assertions | [Positive Lookahead](https://www.hackerrank.com/challenges/positive-lookahead) | Easy | 20 | [](Regex/Assertions/positive-lookahead.java) |
| Assertions | [Negative Lookahead](https://www.hackerrank.com/challenges/negative-lookahead) | Easy | 20 | [](Regex/Assertions/negative-lookahead.java) |
| Assertions | [Positive Lookbehind](https://www.hackerrank.com/challenges/positive-lookbehind) | Easy | 20 | [](Regex/Assertions/positive-lookbehind.java) |
| Assertions | [Negative Lookbehind](https://www.hackerrank.com/challenges/negative-lookbehind) | Easy | 20 | [](Regex/Assertions/negative-lookbehind.java) |