Leetcode solutions

Solved by : Souryadeep Sen
Home page : My home page
All solutions : Using C/C++ programming language.
Source code : src
Headers : headers
Collaboration : I am open to collobaration. Please submit a pull request if there is a better way to solve the problem/there is a bug

Motivation

I created this repo to serve as a reference for others working on leetcode problems, and am working on documenting my approach to solving the problems, which I will publish on this page.
There are always multiple ways to solve problems, as you will see on leetcode too.
I have tried to add in some other best practices such as memory management.
Disclaimer: These do not neccesarily represent the most optimum solution. I am open to collaboration, and feel free to submit a pull request if you would like to contribute to the repo.

Usage

Please see my documentation on installing gcc (compulsory) and other optional tools @ Link

Compiling the code on linux command line:

- For code with comments that mentions 'use with ...'
	- gcc -g -Wall -I../include program.c otherCFiles.c -o test -l(pthread/m/..)   
	- for C++ code, replace the gcc with g++  
	- -I../include is used to tell the compiler where the header files are  
	- other C Files will be in the src directory    
	- -l() is used to tell the linker to link a particular library, such as pthread, math (m) and so on  
	- -g is a debug flag, -Wall is to turn on warnings  
- For code without the above comment
	- gcc -g -Wall program.c -o test -l(pthread/m/...)  

Executing the code on linux command line:

- With valgrind  
	- valgrind --leak-check=yes ./test  <cmdlineoptions>  
- Without valgrind  
	- ./test <cmdlineoptions>

Table of Contents

👷 work in progress...

Type	Question	Difficulty	Comments
Math	1. Pallindrome	Easy
	2. Sqrt	Easy
	3. Pow	Medium
	4. PlusOne	Easy
	5. RomanToInt	Easy
	6. TwoSum	Easy
	7. Reverse Int	Medium
	8. Double Reverse Int	Easy
String	1. LCPrefix	Easy
	2. Valid Parenthesis	Easy
	3. StrStr	Easy
	4. My Atoi	Medium
	5. Longest Substr w/o rep	Medium
	6. Is Pallindrome	Easy
	7. Is Pallindrome 2	Easy
	8. Longest Repeating Substr	Medium	Using hashtable. This is a partially working solution, as implementing the hash table in C is considerably more complex than higher level languages
Array	1. Remove Element	Easy
	2. Next Permutation	Medium
	3. Find Duplicate	Medium	1. Negative marking 2. Bit Manipulation
	4. Max Area	Medium	1. Two pointer 2. Brute Force
	5. Search Insert	Easy
	6. Remove Duplicates	Easy
	7. Merge Sorted Arrays	Easy	3 pointer approach
	8. Search Range	Medium
	9. Find Missing Ranges	Easy
	10.Minimum Buying Cost	Easy
Recursion	1. Reverse List	Easy	use list1.c and list1.h
	2. Merge lists	Easy	use list2.c and list2.h
Bit Manipulation	1. Add Binary	Easy
	2. Reverse Bits	Easy
	3. Hamming Weight	Easy
	4. Alternating Bits	Easy
	5. Subsets	Medium	Solved using bit manipulation.
	6. Missing Number	Easy
	7. Single Number	Easy	Bit manipulation solution
	8. Pallindrome Permutation	Easy
	9. Sum of Two Ints	Medium
	10. Gray Code	Medium	wip
	11. Power of Two	Easy
	12. Power of Four	Easy
	13. Binary Watch	Easy
Hash Table	1. Find the Difference	Easy
	2. First Unique Char	Easy
Concurrency	1. Print in Order	Easy
Dynamic Programming	1. Count Bits	Easy	Bit manipulation also used
	2. Climb Stairs	Easy	Used memoization
	3. Max Sub Array	Easy
	4. Buy/Sell Stock	Easy
	5. Buy/Sell Stock	Medium
	6. Pascal Triangle	Easy
	7. Is Subsequence	Easy
	8. Longest Palindrome Substr	Medium	Around the center method used
Linked List	1. Delete Duplicates	Easy	use list2.h and list2.c
	2. Keep Unique	Medium	use list2.h and list2.c
	3. Swap Pairs	Medium	use list2.c and list2.h
	4. Reverse K Group	Hard	use list2.c and list2.h
	5. Remove Nth element End	Medium	use list2.c and list2.h
	6. Has Cycle	Easy	use list2.c and list2.h
	7. Add 2 nums	Medium
Simulation	1. Fizz Buzz	Easy	Also a string/math Q
Matrix	1. Rotate90	Medium
Interactive	1. First Bad Version	Easy	Binary search implemented
	2. Guess Number	Easy	Binary search implemented
Sorting	1. Majority Element	Easy
	2. Insertion Sort List	Medium
Graph	1. Walls and Gates	Medium
	2. Number of Islands	Medium
	3. Open Lock	Medium
Stack	1. Min Stack	Easy
	2. Reverse Polish	Medium
	3. Num of Islands	Medium	solved with DFS
	4. BST Inorder traverse	Easy
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