leetcode

Welcome to my repository of solutions for LeetCode problems!
Here, you will find my solutions to various coding challenges on Data Structures and Algorithms.
These solutions have been tested and verified to work correctly on the LeetCode platform.

1. Data Structures Problems:

ID	Problem	DIFFICULTY
1	Contains Duplicate	Easy
2	Length of Last Word	Easy
3	Valid Anagram	Easy
4	Replace Elements with Greatest Element on Right Side	Easy
5	Is Subsequence	Easy
6	Two Sum	Easy
7	Remove Element	Easy
8	Longest Common Prefix	Easy
9	Group Anagrams	Medium
10	Majority Element	Easy
11	Next Greater Element I	Easy
12	Unique Email Addresses	Easy
13	Isomorphic Strings	Easy
14	Can Place Flowers	Easy
15	Find Pivot Index	Easy
16	Word Pattern	Easy
17	Top K Frequent Elements	Medium
18	Pascal's Triangle	Easy
19	Plus One	Easy
20	Find All Numbers Disappeared in an Array	Easy
21	Sort Colors	Medium
22	Maximum Number of Balloons	Easy
23	Product of Array Except Self	Medium
24	Valid Sudoku	Medium
25	Longest Consecutive Sequence	Medium
26	Best Time to Buy and Sell Stock II	Medium
27	Best Time to Buy and Sell Stock	Easy
28	Subarray Sum Equals K	Medium
29	Encode and Decode TinyURL	Medium
30	Repeated DNA Sequences	Medium
31	Unique Length-3 Palindromic Subsequences	Medium
32	Largest Number	Medium
33	Find All Anagrams in a String	Medium
34	Minimum Number of Swaps to Make the String Balanced	Medium
35	Merge Sorted Array	Easy
36	Valid Palindrome	Easy
37	Valid Palindrome II	Easy
38	Minimum Difference Between Highest and Lowest of K Scores	Easy
39	Two Sum II - Input Array Is Sorted	Medium
40	Reverse String	Easy
41	Remove Duplicates from Sorted Array	Easy
42	Rotate Array	Medium
43	Move Zeroes	Easy
44	3Sum	Medium
45	Container With Most Water	Medium
46	Boats to Save People	Medium
47	Array With Elements Not Equal to Average of Neighbors	Medium
48	Number of Subsequences That Satisfy the Given Sum Condition	Medium
49	4Sum	Medium
50	Find the Index of the First Occurrence in a String	Medium
51	Trapping Rain Water	Hard
52	Number of Pairs of Interchangeable Rectangles	Medium
53	Insert Delete GetRandom O(1)	Medium

2. SQL:

ID	Problem	DIFFICULTY
1	Big Countries	Easy
2	Recyclable and Low Fat Products	Easy
3	Find Customer Referee	Easy
4	Customers Who Never Order	Easy
5	Calculate Special Bonus	Easy
6	Swap Salary	Easy
7	Delete Duplicate Emails	Easy
8	Fix Names in a Table	Easy
9	Group Sold Products By The Date	Easy
10	Patients With a Condition	Easy
11	Employees With Missing Information	Easy
12	Rearrange Products Table	Easy
13	Tree Node	Medium
14	Article Views I	Easy
15	Invalid Tweets	Easy
16	Replace Employee Id With The Unique Identifier	Easy
17	Product Sales Analysis I	Easy
18	Customer Who Visited but Did Not Make Any Transactions	Easy
19	Rising Temperature	Easy
20	Average Time of Process per Machine	Easy
21	Employee Bonus	Easy
22	Students and Examinations	Easy
23	Managers with at Least 5 Direct Reports	Medium
24	Not Boring Movies	Easy
25	Average Selling Price	Easy
26	Project Employees I	Easy
27	Percentage of Users Attended a Contest	Easy
28	Confirmation Rate	Medium
29	Queries Quality and Percentage	Easy
30	Number of Unique Subjects Taught by Each Teacher	Easy
31	Monthly Transactions I	Medium
32	User Activity for the Past 30 Days I	Easy
33	Immediate Food Delivery II	Medium
34	Game Play Analysis IV	Medium
35	Product Sales Analysis III	Medium
36	Classes More Than 5 Students	Easy
37	Find Followers Count	Easy
38	Biggest Single Number	Easy
39	Customers Who Bought All Products	Medium
40	The Number of Employees Which Report to Each Employee	Easy
41	Primary Department for Each Employee	Easy
42	Triangle Judgement	Easy
43	Consecutive Numbers	Medium
44	Product Price at a Given Date	Medium
45	Last Person to Fit in the Bus	Medium
46	Count Salary Categories	Medium
47	Employees Whose Manager Left the Company	Easy
48	Exchange Seats	Medium
49	Movie Rating	Medium
50	Restaurant Growth	Medium
51	Friend Requests II: Who Has the Most Friends	Medium
52	Investments in 2016	Medium
53	Department Top Three Salaries	Hard
54	Find Users With Valid E-Mails	Easy
55	List the Products Ordered in a Period	Easy
56	Second Highest Salary	Medium
57	Combine Two Tables	Easy
58	Nth Highest Salary	Medium
59	Rank Scores	Medium
60	Employees Earning More Than Their Managers	Easy
61	Duplicate Emails	Easy
62	Department Highest Salary	Medium
63	Find Products with Valid Serial Numbers	Easy
64	Find Valid Emails	Easy
65	Odd and Even Transactions	Medium
66	Find Students Who Improved	Medium