Competitive Programming

This repository contains my solutions to competitive programming problems from various online platforms.

Each of the code solution files contains the problem description, several (differently performing) implementations, as well as time and space complexity analysis.

Table of Contents

• LeetCode
• Hackerrank

LeetCode

#	Difficulty	Problem Title	Implementation
1	Easy	Two Sum	Python
2	Medium	Add Two Numbers	Python
3	Medium	Longest Substring Without Repeating Characters	Python
4	Hard	Median Of Two Sorted Arrays	Python
5	Medium	Longest Palindromic Substring	Python
6	Medium	Zigzag Conversion	Python
7	Medium	Reverse Integer	Python
8	Medium	String To Integer (Atoi)	Python
10	Hard	Regular Expression Matching	Python
11	Medium	Container With Most Water	Python
13	Easy	Roman to Integer	Python
14	Easy	Longest Common Prefix	Python
15	Medium	3Sum	Python
17	Medium	Letter Combinations of a Phone Number	Python
19	Medium	Remove Nth Node From End of List	Python
20	Easy	Valid Parentheses	Python
21	Easy	Merge Two Sorted Lists	Python
22	Medium	Generate Parentheses	Python
26	Easy	Remove Duplicates from Sorted Array	Python
28	Easy	Find The Index Of The First Occurrence In A String	Python
36	Medium	Valid Sudoku	Python
42	Hard	Trapping Rain Water	Python
45	Medium	Jump Game II	Python
49	Medium	Group Anagrams	Python
50	Medium	Pow(X, N)	Python
51	Hard	N-Queens	Python
53	Medium	Maximum Subarray	Python
54	Medium	Spiral Matrix	Python
55	Medium	Jump Game	Python
70	Easy	Climbing Stairs	Python
94	Easy	Binary Tree Inorder Traversal	Python
100	Easy	Same Tree	Python
121	Easy	Best Time To Buy And Sell Stock	Python
125	Easy	Valid Palindrome	Python
128	Medium	Longest Consecutive Sequence	Python
133	Medium	Clone Graph	Python
136	Easy	Single Number	Python
144	Easy	Binary Tree Preorder Traversal	Python
145	Easy	Binary Tree Postorder Traversal	Python
151	Medium	Reverse Words in a String	Python
152	Medium	Maximum Product Subarray	Python
153	Medium	Find Minimum in Rotated Sorted Array	Python
155	Medium	Min Stack	Python
167	Medium	Two Sum Ii - Input Array Is Sorted	Python
179	Medium	Largest Number	Python
200	Medium	Number of Islands	Python
206	Easy	Reverse Linked List	Python
207	Medium	Course Schedule	Python
210	Medium	Course Schedule Ii	Python
217	Easy	Contains Duplicate	Python
225	Easy	Implement Stack using Queues	Python
226	Easy	Invert Binary Tree	Python
232	Easy	Implement Queue using Stacks	Python
238	Medium	Product of Array Except Self	Python
242	Easy	Valid Anagram	Python
263	Easy	Ugly Number	Python
264	Medium	Ugly Number II	Python
268	Easy	Missing Number	Python
271	Medium	Encode And Decode Strings	Python
292	Easy	Nim Game	Python
300	Medium	Longest Increasing Subsequence	Python
345	Easy	Reverse Vowels of a String	Python
370	Medium	Range Addition	Python
430	Medium	Flatten a Multilevel Doubly Linked List	Python
443	Medium	String Compression	Python
450	Medium	Delete Node In A Bst	Python
476	Easy	Number Complement	Python
485	Easy	Max Consecutive Ones	Python
487	Medium	Max Consecutive Ones Ii	Python
496	Easy	Next Greater Element I	Python
503	Medium	Next Greater Element II	Python
557	Easy	Reverse Words in a String III	Python
572	Easy	Subtree of Another Tree	Python
633	Medium	Sum Of Square Numbers	Python
692	Medium	Top K Frequent Words	Python
701	Medium	Insert Into A Binary Search Tree	Python
706	Easy	Design HashMap	Python
735	Medium	Asteroid Collision	Python
739	Medium	Daily Temperatures	Python
743	Medium	Network Delay Time	Python
771	Easy	Jewels and Stones	Python
874	Medium	Walking Robot Simulation	Python
945	Medium	Minimum Increment To Make Array Unique	Python
1052	Medium	Grumpy Bookstore Owner	Python
1106	Hard	Parsing A Boolean Expression	Python
1137	Easy	N-Th Tribonacci Number	Python
1143	Medium	Longest Common Subsequence	Python
1207	Easy	Unique Number of Occurrences	Python
1275	Easy	Find Winner on a Tic Tac Toe Game	Python
1304	Easy	Find N Unique Integers Sum up to Zero	Python
1431	Easy	Kids With the Greatest Number of Candies	Python
1443	Medium	Minimum Time To Collect All Apples In A Tree	Python
1518	Easy	Water Bottles	Python
1578	Medium	Minimum Time to Make Rope Colorful	Python
1636	Easy	Sort Array By Increasing Frequency	Python
1653	Medium	Minimum Deletions to Make String Balanced	Python
1717	Medium	Maximum Score From Removing Substrings	Python
1768	Easy	Merge Strings Alternately	Python
1822	Easy	Sign of the Product of an Array	Python
1894	Medium	Find the Student that Will Replace the Chalk	Python
2028	Medium	Find Missing Observations	Python
2037	Easy	Minimum Number Of Moves To Seat Everyone	Python
2085	Easy	Count Common Words With One Occurrence	Python
2259	Easy	Remove Digit From Number to Maximize Result	Python
3163	Medium	String Compression III	Python

Hackerrank

Array

Difficulty	Problem Title	Implementation
Easy	Arrays - DS	Python
Easy	Array Left Rotation	Python

Linked Lists

Difficulty	Problem Title	Implementation
Easy	Reverse a Linked List	Python

Programming Language Choices

Why Python? I think Python is a good language for quickly writing elegant and readable programs. Of course, performance will be compromised, but performance is not the main goal of this project (for now). I am mostly solving these puzzles to improve my knowledge in Algorithms and Data Structures.