Hackerrank Practice Problems

• This repository contains solutions to Hackerrank practice problems in SQL, C++, Java or Python.
• If you are interested in adding more Hackerrank problem solutions, please feel free to contribute.
• If you feel this repo is helpful for you, please do star it.
• If you are a hacktoberfest contributor, claim only one issue at a time from this repository and a maximum of two issues for hacktoberfest contribution.
• Kindly follow CODE_OF_CONDUCT.md and CONTRIBUTING.md before contributing.
• Happy Coding 🥳!

Topics

SQL

• Basic Select
• Advanced Select
• Aggregation
• Basic Join
• Advanced Join
• Alternative Queries

C++

• Introduction
• Strings

Java

• Introduction

Python

• Introduction
• Basic Data Types

SQL (All the solutions are given in MySQL)

Basic Select

S.No.	Problem	Solution	Score	Difficulty
01.	Revising the Select Query I	Solution	10	Easy
02.	Revising the Select Query II	Solution	10	Easy
03.	Select All	Solution	10	Easy
04.	Select By ID	Solution	10	Easy
05.	Japanese Cities' Attributes	Solution	10	Easy
06.	Japanese Cities' Names	Solution	10	Easy
07.	Weather Observation Station 1	Solution	15	Easy
08.	Weather Observation Station 3	Solution	10	Easy
09.	Weather Observation Station 4	Solution	10	Easy
10.	Weather Observation Station 5	Solution	30	Easy
11.	Weather Observation Station 6	Solution	10	Easy
12.	Weather Observation Station 7	Solution	10	Easy
13.	Weather Observation Station 8	Solution	15	Easy
14.	Weather Observation Station 9	Solution	10	Easy
15.	Weather Observation Station 10	Solution	10	Easy
16.	Weather Observation Station 11	Solution	15	Easy
17.	Weather Observation Station 12	Solution	15	Easy
18.	Higher Than 75 Marks	Solution	15	Easy
19.	Employee Names	Solution	10	Easy
20.	Employee Salaries	Solution	10	Easy

Advanced Select

S.No.	Problem	Solution	Score	Difficulty
01.	Type of Triangle	Solution	20	Easy
02.	The PADS	Solution	30	Medium
03.	Occupations	Solution	30	Medium
04.	Binary Tree Nodes	Solution	30	Medium
05.	New Companies	Solution	30	Medium

Aggregation

S.No.	Problem	Solution	Score	Difficulty
01.	Revising Aggregations - The Count Function	Solution	10	Easy
02.	Revising Aggregations - The Sum Function	Solution	10	Easy
03.	Revising Aggregations - Averages	Solution	10	Easy
04.	Average Population	Solution	10	Easy
05.	Japan Population	Solution	10	Easy
06.	Population Density Difference	Solution	10	Easy
07.	The Blunder	solution	15	Easy
08.	Top Earners	Solution	20	Easy
09.	Weather Observation Station 2	Solution	15	Easy
10.	Weather Observation Station 13	Solution	10	Easy
11.	Weather Observation Station 14	Solution	10	Easy
12.	Weather Observation Station 15	Solution	15	Easy
13.	Weather Observation Station 16	Solution	10	Easy
14.	Weather Observation Station 17	Solution	15	Easy
15.	Weather Observation Station 18	Solution	25	Medium
16.	Weather Observation Station 19	Solution	30	Medium
17.	Weather Observation Station 20	Solution	40	Medium

Basic Join

S.No.	Problem	Solution	Score	Difficulty
01.	Population Census	Solution	10	Easy
02.	African Cities	Solution	10	Easy
03.	Average Population of Each Continent	Solution	10	Easy
04.	The Report	Solution	20	Medium
05.	Top Competitors	Solution	30	Medium
06.	Ollivander's Inventory	Solution	30	Medium
07.	Challenges	Solution	30	Medium
08.	Contest Leaderboard	Solution	30	Medium

Advanced Join

S.No.	Problem	Solution	Score	Difficulty
01.	SQL Project Planning	Solution	40	Medium

Alternative Queries

S.No.	Problem	Solution	Score	Difficulty
01.	Draw The Triangle 1	Solution	25	Easy
02.	Draw The Triangle 2	Solution	25	Easy

C++

Introduction

| S.No. | Problem | Solution | Score | Difficulty | | 01. | Conditional Statements | Solution | 10 | Easy |

02.	Arrays Introduction	Solution	10	Easy

Strings

S.No.	Problem	Solution	Score	Difficulty

Java

Introduction

S.No.	Problem	Solution	Score	Difficulty
1	Java Stdin and Stdout	Solution	10	Easy

Strings

S.No.	Problem	Solution	Score	Difficulty

Python

Introduction

S.No.	Problem	Solution	Score	Difficulty
01.	Division	Solution	10	Easy
02.	Write a Function	Solution	10	Medium

Basic Data Types

S.No.	Problem	Solution	Score	Difficulty
01.	List Comprehensions	Solution	10	Easy