Competitive-Programming Repository

This repostitory contains code for following-

1. Basic Concepts -
   1. Algorithms
      1. Basic Graph Algorithms
      2. Basic Sorting Algorithms
      3. Basic Recursion Algorithms
      4. Basic Dynamic Programming Algorithms
      5. Basic Greedy Algorithms
      6. Basic Mathematics
   2. Basic Data Structures
2. GeeksForGeeks
   1. Algorithms
3. HackerRank
   1. Algorithms
      1. HackerRank Sorting
      2. HackerRank Strings
      3. HackerRank Graph Theory
      4. HackerRank Dynamic Programming
4. HackerEarth
   1. HackerEarth
   2. CodeMonk
   3. HiringChallenges
5. CodeChef
6. LeetCode

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Problems - Solutions

Basic Concepts

Basic Graph Algorithms

#	Title	Solution	Time	Space
1	Adjacency List Undirected	java
2	Adjacency Matrix Directed	java
3	Adjacency Matrix Undirected	java
4	BFS Directed	java
5	BFS Undirected	java
6	Connected Components Undirected Graph	java	O(|V + E|)	O(|V|)
7	Detect Cycle in Undirected Graph using Union and Find	java	O(|V * log(V)|)	O(|V + E|)

Basic Sorting Algorithms

#	Title	Solution	Time	Space	Notes
1	Bubble Sort	java	W(|N|) O(|N*N|)	O(|1|)	In-Place, Stable
2	Recursive Bubble Sort	java	W(|N|) O(|N*N|)	O(|1|)	In-Place, Stable
3	Counting Sort	java
4	Insertion Sort	java	W(|N|) O(|N*N|)	O(|1|)	In-Place, Stable, Online
5	Recursive Insertion Sort	java	W(|N|) O(|N*N|)	O(|1|)	In-Place, Stable, Online
6	Radix Sort	java
7	Selection Sort	java
8	Merge Sort	java	O(|N*log(N)|)	O(|N|)	Stable
9	Merge Sort Linked List	java	O(|N*log(N)|)	O(|N|)	Stable
10	Iterative Merge Sort	java	O(|N*log(N)|)	O(|N|)	Stable
11	Quick Sort	java	O(|N*log(N)|)	O(|1|)	In-Place, Stable
12	Iterative Quick Sort	java	O(|N*log(N)|)	O(|1|)	In-Place, Stable

Basic Recursion Algorithms

#	Title	Solution	Time	Space	Notes
1	Factorial	java	O(|N*N|)	O(|1|)
2	Permutation of a given String	java
3	Selection Sort Recursive	java

Basic Dynamic Programming Algorithms

#	Title	Solution	Time	Space	Notes
1	Fibonacci Number DP	java	O(|N|)	O(|N|)
2	Fibonacci Number with Recursion	java	O(|2^N|)	O(|N|)
3	Fibonacci Series with Recursion	java	O(|N|)	O(|1|)
4	Fibonacci Series without Recursion	java	O(|N|)	O(|1|)
5	Edit/Levenshtein Distance	java	O(|M*N|)	O(|M*N|)
6	Min Cost Path	java	O(|M*N|)	O(|M*N|)

Basic Greedy Algorithms

#	Title	Solution	Time	Space	Notes
1	Sorted Activity Selection Problem	java	O(|N|)	O(|1|)
2	Unsorted Activity Selection Problem	java	O(|N*log(N)|)	O(|1|)
3	Kruskal Minimum Spanning Tree	java	O(|Elog(E)|) or O(|Elog(V)|)	O(|V + E|)

Basic Mathematics

#	Title	Solution	Time	Space	Notes
1	Prime Factors	c++	O(|log(N)|)	O(|1|)
2	Sieve of Eratosthenes	c++	O(|N*log(log(N))|)	O(|N|)

Basic Data Structures

#	Title	Solution	Time	Space	Notes
1	Disjoint Set	java	O(|log(N)|)	O(|N|)	Using Path Compression and Union by Rank

Geeks For Geeks Algorithms

#	Problem	Solution	Time	Space
1	Largest Even Number	java
2	Palindrome String	java
3	Sum Of Digit Is Palindrome Or Not	java
4	X Total Shapes	java
5	Floyd Tortoise and Hare	java	O(|N|)
6	Sort The Array	java	O(|N*log(N)|)
7	N Meetings in One Room	java	O(|N*log(N)|)
8	Detect Cycle in Directed Graph	java	O(|V + E|)
9	Edit Distance	java	O(|M*N|)
10	Highest Prime	c++
11	Largest Prime Factor	c++
12	Path in Matrix	java
13	Least Prime Factor	C++
14	Check for Subsequence	C++

HackerRank

HackerRank Sorting

#	Problem	Solution	Time	Space	Difficulty	Points
1	Big Sorting	java			Easy	20
2	Insertion Sort 1	java	O(|N*N|)	O(|1|)	Easy	30
3	Insertion Sort 2	java	O(|N*N|)	O(|1|)	Easy	30

HackerRank Strings

#	Problem	Solution	Time	Space	Difficulty	Points
1	Beautiful Binary String	java			Easy	20
2	Gemstones	java			Easy	20
3	Making Anagrams	java			Easy	30
4	Mars Exploration	java			Easy	15
5	The Love Letter Mystery	java			Easy	20
6	Game of Thrones 1	java	O(|N|)	O(|1|)	Easy	30
7	Anagram	java	O(|N|)	O(|1|)	Easy	25
8	Two Strings	java	O(|N|)	O(|1|)	Easy	25

HackerRank Graph Theory

#	Problem	Solution	Time	Space	Difficulty	Points
1	Roads and Libraries	java	O(|V|)	O(|V|)	Medium	30
2	Journey to the Moon	java	O(|V + E|)	O(|V|)	Medium	50

HackerRank Dynamic Programming

#	Problem	Solution	Time	Space	Difficulty	Points
1	Fibonacci Modified	java	O(|N|)	O(|1|)	Medium	45
2	The Coin Change Problem	java	O(|total*coins|)	O(|total|)	Hard	60

HackerEarth

#	Problem	Solution	Time	Space	Points	Notes
1	Alex And Priority Queues	java
2	Alex And Requests	java
3	Disconnected Graph	java
4	Sum of Subsets	java
5	RhezoAndBigPowers	java			30	Used BigInteger build in modPow() function
6	Roy And Trains	java			20
6	Roy And Wobbly Numbers	java			20
7	Sherlock And Dates	java			20
8	The Best Player	java			20
9	Crazy Matrix	java			30
10	Crushing Violence	java			20
10	Fizz Buzz	java C++			20

HackerEarth CodeMonk

1. Basics of Input Output
2. BitManipulation

HackerEarth Hiring Challenges

#	Problem	Solution	Time	Space	Points	Notes
1	Find The String	java / python
2	Fredo and Two Strings	cpp / java

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Follow my progress -

1. Hacker Rank
2. Geeks for Geeks
3. Hacker Earth
4. Code Chef
5. Leet Code
6. Linkedin