LeetCode Solutions # Title Python C SQL Difficulty 1 Two Sum 1.py 1.c Easy 2 Add Two Numbers 2.py 2.c Medium 3 Longest Substring Without Repeating Characters 3.py Medium 4 Median of Two Sorted Arrays 4.py Hard 5 Longest Palindromic Substring 5.py Medium 6 Zigzag Conversion 6.py Medium 7 Reverse Integer 7.py Medium 8 String to Integer (atoi) 8.py Medium 9 Palindrome Number 9.py Easy 10 Regular Expression Matching 10.py Hard 11 Container With Most Water 11.py Medium 12 Integer to Roman 12.py Medium 13 Roman to Integer 13.py Easy 14 Longest Common Prefix 14.py Easy 15 3Sum 15.py Medium 16 3Sum Closest 16.py Medium 17 Letter Combinations of a Phone Number 17.py Medium 18 4Sum 18.py Medium 19 Remove Nth Node From End of List 19.py Medium 20 Valid Parentheses 20.py Easy 21 Merge Two Sorted Lists 21.py Easy 22 Generate Parentheses 22.py Medium 23 Merge k Sorted Lists 23.py Hard 24 Swap Nodes in Pairs 24.py Medium 25 Reverse Nodes in k-Group 25.py Hard 26 Remove Duplicates from Sorted Array 26.py Easy 27 Remove Element 27.py Easy 28 Find the Index of the First Occurrence in a String 28.py Easy 29 Divide Two Integers 29.py Medium 30 Substring with Concatenation of All Words 30.py Hard 31 Next Permutation 31.py Medium 32 Longest Valid Parentheses 32.py Hard 33 Search in Rotated Sorted Array 33.py Medium 34 Find First and Last Position of Element in Sorted Array 34.py Medium 35 Search Insert Position 35.py Easy 36 Valid Sudoku 36.py Medium 37 Sudoku Solver 37.py Hard 38 Count and Say 38.py Medium 39 Combination Sum 39.py Medium 40 Combination Sum II 40.py Medium 41 First Missing Positive 41.py Hard 42 Trapping Rain Water 42.py Hard 43 Multiply Strings 43.py Medium 44 Wildcard Matching 44.py Hard 45 Jump Game II 45.py Medium 46 Permutations 46.py Medium 47 Permutations II 47.py Medium 48 Rotate Image 48.py Medium 49 Group Anagrams 49.py Medium 50 Pow(x, n) 50.py Medium 53 Maximum Subarray 53.py Medium 54 Spiral Matrix 54.py Medium 55 Jump Game 55.py Medium 56 Merge Intervals 56.py Medium 57 Insert Interval 57.py Medium 58 Length of Last Word 58.py Easy 59 Spiral Matrix II 59.py Medium 60 Permutation Sequence 60.py Hard 61 Rotate List 61.py Medium 62 Unique Paths 62.py Medium 63 Unique Paths II 63.py Medium 64 Minimum Path Sum 64.py Medium 66 Plus One 66.py Easy 67 Add Binary 67.py Easy 69 Sqrt(x) 69.py Easy 70 Climbing Stairs 70.py Easy 71 Simplify Path 71.py Medium 73 Set Matrix Zeroes 73.py Medium 74 Search a 2D Matrix 74.py Medium 75 Sort Colors 75.py Medium 77 Combinations 77.py Medium 78 Subsets 78.py Medium 79 Word Search 79.py Medium 80 Remove Duplicates from Sorted Array II 80.py Medium 81 Search in Rotated Sorted Array II 81.py Medium 83 Remove Duplicates from Sorted List 83.py Easy 88 Merge Sorted Array 88.py Easy 94 Binary Tree Inorder Traversal 94.py Easy 100 Same Tree 100.py Easy 112 Path Sum 112.py Easy 116 Populating Next Right Pointers in Each Node 116.py Medium 118 Pascal's Triangle 118.py Easy 119 Pascal's Triangle II 119.py Easy 120 Triangle 120.py Medium 125 Valid Palindrome 125.py Easy 136 Single Number 136.py Easy 167 Two Sum II - Input Array Is Sorted 167.py Medium 169 Majority Element 169.py Easy 175 Combine Two Tables 175.sql Easy 176 Second Highest Salary 176.sql Medium 177 Nth Highest Salary 177.sql Medium 178 Rank Scores 178.sql Medium 180 Consecutive Numbers 180.sql Medium 181 Employees Earning More Than Their Managers 181.sql Easy 182 Duplicate Emails 182.sql Easy 183 Customers Who Never Order 183.sql Easy 184 Department Highest Salary 184.sql Medium 185 Department Top Three Salaries 185.sql Hard 189 Rotate Array 189.py Medium 190 Reverse Bits 190.py Easy 191 Number of 1 Bits 191.py Easy 196 Delete Duplicate Emails 196.sql Easy 197 Rising Temperature 197.sql Easy 198 House Robber 198.py Medium 206 Reverse Linked List 206.py Easy 231 Power of Two 231.py Easy 278 First Bad Version 278.py Easy 283 Move Zeroes 283.py Easy 344 Reverse String 344.py Easy 345 Reverse Vowels of a String 345.py Easy 511 Game Play Analysis I 511.sql Easy 542 01 Matrix 542.py Medium 550 Game Play Analysis IV 550.sql Medium 557 Reverse Words in a String III 557.py Easy 567 Permutation in String 567.py Medium 570 Managers with at Least 5 Direct Reports 570.sql Medium 577 Employee Bonus 577.sql Easy 584 Find Customer Referee 584.sql Easy 585 Investments in 2016 585.sql Medium 586 Customer Placing the Largest Number of Orders 586.sql Easy 595 Big Countries 595.sql Easy 596 Classes More Than 5 Students 596.sql Easy 602 Friend Requests II: Who Has the Most Friends 602.sql Medium 605 Can Place Flowers 605.py Easy 607 Sales Person 607.sql Easy 608 Tree Node 608.sql Medium 610 Triangle Judgement 610.sql Easy 617 Merge Two Binary Trees 617.py Easy 619 Biggest Single Number 619.sql Easy 620 Not Boring Movies 620.sql Easy 626 Exchange Seats 626.sql Medium 627 Swap Salary 627.sql Easy 695 Max Area of Island 695.py Medium 704 Binary Search 704.py Easy 733 Flood Fill 733.py Easy 784 Letter Case Permutation 784.py Medium 876 Middle of the Linked List 876.py Easy 977 Squares of a Sorted Array 977.py Easy 994 Rotting Oranges 994.py Medium 1045 Customers Who Bought All Products 1045.sql Medium 1050 Actors and Directors Who Cooperated At Least Three Times 1050.sql Easy 1068 Product Sales Analysis I 1068.sql Easy 1070 Product Sales Analysis III 1070.sql Medium 1071 Greatest Common Divisor of Strings 1071.py Easy 1075 Project Employees I 1075.sql Easy 1084 Sales Analysis III 1084.sql Easy 1141 User Activity for the Past 30 Days I 1141.sql Easy 1148 Article Views I 1148.sql Easy 1158 Market Analysis I 1158.sql Medium 1164 Product Price at a Given Date 1164.sql Medium 1174 Immediate Food Delivery II 1174.sql Medium 1179 Reformat Department Table 1179.sql Easy 1193 Monthly Transactions I 1193.sql Medium 1204 Last Person to Fit in the Bus 1204.sql Medium 1211 Queries Quality and Percentage 1211.sql Easy 1251 Average Selling Price 1251.sql Easy 1280 Students and Examinations 1280.sql Easy 1321 Restaurant Growth 1321.sql Medium 1327 List the Products Ordered in a Period 1327.sql Easy 1341 Movie Rating 1341.sql Medium 1378 Replace Employee ID With The Unique Identifier 1378.sql Easy 1393 Capital Gain/Loss 1393.sql Medium 1407 Top Travellers 1407.sql Easy 1431 Kids With the Greatest Number of Candies 1431.py Easy 1484 Group Sold Products By The Date 1484.sql Easy 1517 Find Users With Valid E-Mails 1517.sql Easy 1527 Patients With a Condition 1527.sql Easy 1581 Customer Who Visited but Did Not Make Any Transactions 1581.sql Easy 1587 Bank Account Summary II 1587.sql Easy 1633 Percentage of Users Attended a Contest 1633.sql Easy 1661 Average Time of Process per Machine 1661.sql Easy 1667 Fix Names in a Table 1667.sql Easy 1683 Invalid Tweets 1683.sql Easy 1693 Daily Leads and Partners 1693.sql Easy 1729 Find Followers Count 1729.sql Easy 1731 The Number of Employees Which Report to Each Employee 1731.sql Easy 1741 Find Total Time Spent by Each Employee 1741.sql Easy 1757 Recyclable and Low Fat Products 1757.sql Easy 1768 Merge Strings Alternately 1768.py Easy 1789 Primary Department for Each Employee 1789.sql Easy 1795 Rearrange Products Table 1795.sql Easy 1873 Calculate Special Bonus 1873.sql Easy 1890 The Latest Login in 2020 1890.sql Easy 1907 Count Salary Categories 1907.sql Medium 1934 Confirmation Rate 1934.sql Medium 1965 Employees With Missing Information 1965.sql Easy 1978 Employees Whose Manager Left the Company 1978.sql Easy 2356 Number of Unique Subjects Taught by Each Teacher 2356.sql Easy