petrosDemetrakopoulos/Leetcode

My Leetcode solutions

My Leetcode solutions

For most most of the Leetcode tasks I used Python.

Of course for the SQL and Bash scripting tasks I used the respective languages.

Here is a list of all the tasks along with their id and difficulty.

The format of each filename is: '{task_code}-{task_name_camelcase}.py'

The following table shows all the problems I have completed in Leetcode. The first column (Leetcode ID) has link to the respective problem page at Leetcode, while the 3rd column (Solution) links to my solution in this GitHub repo.

Content

Leetcode ID	Title	Difficulty	Solution
1	Two Sum	Easy	Python
2	Add Two Numbers	Medium	Python
7	Reverse integer	Medium	Python
8	String to integer (atoi)	Medium	Python
9	Palindrome Number	Easy	Python
11	Container With Most Water	Medium	Python
13	Roman to Integer	Easy	Python
14	Longest Common Prefix	Easy	Python
17	Letter Combinations of a Phone Number	Medium	Python
20	Valid Parentheses	Easy	Python
21	Merge Two Sorted Lists	Easy	Python
26	Remove Duplicates from Sorted Array	Easy	Python
27	Remove Element	Easy	Python
28	Implement strStr()	Easy	Python
34	Find First and Last Position of Element in Sorted Array	Medium	Python
35	Search Insert Position	Easy	Python
36	Valid Sudoku	Medium	Python
46	Permutations	Medium	Python
47	Permutations II	Medium	Python
48	Rotate Image	Medium	Python
49	Group Anagrams	Medium	Python
50	Pow(x, n)	Medium	Python
53	Maximum Subarray	Medium	Python
58	Length of Last Word	Easy	Python
66	Plus One	Easy	Python
67	Add Binary	Easy	Python
69	Sqrt(x)	Easy	Python
70	Climbing Stairs	Easy	Python
73	Set Matrix Zeroes	Medium	Python
74	Search a 2D Matrix	Medium	Python
75	Sort Colors	Medium	Python
77	Combinations	Medium	Python
78	Subsets	Medium	Python
83	Remove Duplicates from Sorted List	Easy	Python
94	Binary Tree Inorder Traversal	Easy	Python
100	Same Tree	Easy	Python
104	Maximum Depth of Binary Tree	Easy	Python
108	Convert Sorted Array to Binary Search Tree	Easy	Python
111	Minimum Depth of Binary Tree	Easy	Python
114	Flatten Binary Tree to Linked List	Medium	Python
118	Pascal's Triangle	Easy	Python
119	Pascal's Triangle II	Easy	Python
121	Best Time to Buy and Sell Stock	Easy	Python
125	Valid Palindrome	Easy	Python
136	Single Number	Easy	Python
141	Linked List Cycle	Easy	Python
142	Linked List Cycle II	Medium	Python
144	Binary Tree Preorder Traversal	Easy	Python
145	Binary Tree Postorder Traversal	Easy	Python
148	Sort List	Medium	Python
151	Reverse Words in a String	Medium	Python
153	Find Minimum in Rotated Sorted Array	Medium	Python
168	Excel Sheet Column Title	Easy	Python
169	Majority Element	Easy	Python
171	Excel Sheet Column Number	Easy	Python
175	Combine Two Tables	Easy	SQL
176	Second Highest Salary	Medium	SQL
177	Nth Highest Salary	Medium	SQL
178	Rank Scores	Medium	SQL
181	Employees Earning More Than Their Managers	Easy	SQL
182	Duplicate Emails	Easy	SQL
183	Customers Who Never Order	Easy	SQL
184	Department Highest Salary	Medium	SQL
187	Repeated DNA Sequences	Medium	Python
190	Reverse Bits	Easy	Python
191	Number of 1 Bits	Easy	Python
192	Word Frequency	Medium	Python
193	Valid Phone Numbers	Easy	Bash script
195	Tenth Line	Easy	Bash script
196	Delete Duplicate Emails	Easy	SQL
197	Rising Temperature	Easy	SQL
202	Happy Number	Easy	Python
206	Reverse Linked List	Easy	Python
215	Kth Largest Element in an Array	Medium	Python
216	Combination Sum III	Medium	Python
217	Contains Duplicate	Easy	Python
226	Invert Binary Tree	Easy	Python
231	Power of Two	Easy	Python
234	Palindrome Linked List	Easy	Python
237	Delete Node in a Linked List	Easy	Python
240	Search a 2D Matrix II	Medium	Python
242	Valid Anagram	Easy	Python
258	Add Digits	Easy	Python
268	Missing Number	Easy	Python
278	First Bad Version	Easy	Python
283	Move Zeroes	Easy	Python
287	Find The Duplicate Number	Medium	Python
290	Word Pattern	Easy	Python
303	Range Sum Query - Immutable	Easy	Python
319	Bulb Switcher	Medium	Python
326	Power of Three	Easy	Python
338	Counting Bits	Easy	Python
342	Power of Four	Easy	Python
344	Reverse String	Easy	Python
345	Reverse Vowels of a String	Easy	Python
347	Top K Frequent Elements	Medium	Python
349	Intersection of Two Arrays	Easy	Python
350	Intersection of Two Arrays II	Easy	Python
367	Valid Perfect Square	Easy	Python
374	Guess Number Higher or Lower	Easy	Python
378	Kth Smallest Element in a Sorted Matrix	Medium	Python
383	Ransom Note	Easy	Python
387	First Unique Character in a String	Easy	Python
389	Find the Difference	Easy	Python
412	Fizz Buzz	Easy	Python
414	Third Maximum Number	Easy	Python
434	Number of Segments in a String	Easy	Python
442	Find All Duplicates in an Array	Medium	Python
451	Sort Characters By Frequency	Medium	Python
461	Hamming Distance	Easy	Python
476	Number Complement	Easy	Python
485	Max Consecutive Ones	Easy	Python
496	Next Greater Element I	Easy	Python
500	Keyboard Row	Easy	Python
501	Find Mode in Binary Search Tree	Easy	Python
509	Fibonacci Number	Easy	Python
511	Game Play Analysis I	Easy	SQL
520	Detect Capital	Easy	Python
535	Encode and Decode TinyURL	Medium	Python
551	Student Attendance Record I	Easy	Python
557	Reverse Words in a String III	Easy	Python
559	Maximum Depth of N-ary Tree	Easy	Python
561	Array Partition	Easy	Python
566	Reshape the Matrix	Easy	Python
575	Distribute Candies	Easy	Python
584	Find Customer Referee	Easy	SQL
586	Customer Placing the Largest Number of Orders	Easy	SQL
589	N-ary Tree Preorder Traversal	Easy	Python
590	N-ary Tree Postorder Traversal	Easy	Python
593	Valid Square	Medium	Python
595	Big Countries	Easy	SQL
596	Classes More Than 5 Students	Easy	SQL
598	Range Addition II	Easy	Python
606	Construct String from Binary Tree	Easy	Python
607	Sales Person	Easy	SQL
608	Tree Node	Medium	SQL
620	Not Boring Movies	Easy	SQL
627	Swap Salary	Easy	SQL
628	Maximum Product of Three Numbers	Easy	Python
637	Average of Levels in Binary Tree	Easy	Python
648	Replace Words	Medium	Python
657	Robot Return to Origin	Easy	Python
692	Top K Frequent Words	Medium	Python
693	Binary Number with Alternating Bits	Easy	Python
700	Search in a Binary Search Tree	Easy	Python
704	Binary Search	Easy	Python
705	Design HashSet	Easy	Python
706	Design HashMap	Easy	Python
709	To Lower Case	Easy	Python
724	Find Pivot Index	Easy	Python
728	Self Dividing Numbers	Easy	Python
729	My Calendar I	Medium	Python
744	Find Smallest Letter Greater Than Target	Easy	Python
747	Largest Number At Least Twice of Others	Easy	Python
762	Prime Number of Set Bits in Binary Representation	Easy	Python
766	Toeplitz Matrix	Easy	Python
771	Jewels and Stones	Easy	Python
796	Rotate String	Easy	Python
804	Unique Morse Code Words	Easy	Python
806	Number of Lines To Write String	Easy	Python
819	Most Common Word	Easy	Python
821	Shortest Distance to a Character	Easy	Python
824	Goat Latin	Easy	Python
832	Flipping an Image	Easy	Python
836	Rectangle Overlap	Easy	Python
867	Transpose Matrix	Easy	Python
868	Binary Gap	Easy	Python
876	Middle of the Linked List	Easy	Python
884	Uncommon Words from Two Sentences	Easy	Python
905	Sort Array By Parity	Easy	Python
917	Reverse Only Letters	Easy	Python
922	Sort Array By Parity II	Easy	Python
933	Number of Recent Calls	Easy	Python
938	Range Sum of BST	Easy	Python
944	Delete Columns to Make Sorted	Easy	Python
961	N-Repeated Element in Size 2N Array	Easy	Python
965	Univalued Binary Tree	Easy	Python
976	Largest Perimeter Triangle	Easy	Python
977	Squares of a Sorted Array	Easy	Python
989	Add to Array-Form of Integer	Easy	Python
997	Find the Town Judge	Easy	Python
1009	Complement of Base 10 Integer	Easy	Python
1046	Last Stone Weight	Easy	Python
1047	Remove All Adjacent Duplicates In String	Easy	Python
1050	Actors and Directors Who Cooperated At Least Three Times	Easy	SQL
1051	Height Checker	Easy	Python
1084	Sales Analysis III	Easy	SQL
1108	Defanging an IP Address	Easy	Python
1114	Print in Order	Easy	Python
1137	N-th Tribonacci Number	Easy	Python
1141	User Activity for the Past 30 Days I	Easy	SQL
1148	Article Views I	Easy	SQL
1154	Day of the Year	Easy	Python
1158	Market Analysis I	Medium	SQL
1160	Find Words That Can Be Formed by Characters	Easy	Python
1179	Reformat Department Table	Easy	SQL
1185	Day of the Week	Easy	Python
1189	Maximum Number of Balloons	Easy	Python
1207	Unique Number of Occurrences	Easy	Python
1217	Minimum Cost to Move Chips to The Same Position	Easy	Python
1221	Split a String in Balanced Strings	Easy	Python
1232	Check If It Is a Straight Line	Easy	Python
1252	Cells with Odd Values in a Matrix	Easy	Python
1281	Subtract the Product and Sum of Digits of an Integer	Easy	Python
1282	Group the People Given the Group Size They Belong To	Medium	Python
1287	Element Appearing More Than 25% In Sorted Array	Easy	Python
1290	Convert Binary Number in a Linked List to Integer	Easy	Python
1295	Find Numbers with Even Number of Digits	Easy	Python
1299	Replace Elements with Greatest Element on Right Side	Easy	Python
1309	Decrypt String from Alphabet to Integer Mapping	Easy	Python
1313	Decompress Run-Length Encoded List	Easy	Python
1323	Maximum 69 Number	Easy	Python
1324	Print Words Vertically	Medium	Python
1325	Delete Leaves With a Given Value	Medium	Python
1337	The K Weakest Rows in a Matrix	Easy	Python
1338	Reduce Array Size to The Half	Medium	Python
1342	Number of Steps to Reduce a Number to Zero	Easy	Python
1346	Check If N and Its Double Exist	Easy	Python
1351	Count Negative Numbers in a Sorted Matrix	Easy	Python
1365	How Many Numbers Are Smaller Than the Current Number	Easy	Python
1374	Generate a String With Characters That Have Odd Counts	Easy	Python
1379	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Easy	Python
1380	Lucky Numbers in a Matrix	Easy	Python
1385	Find the Distance Value Between Two Arrays	Easy	Python
1387	Sort Integers by The Power Value	Medium	Python
1393	Capital Gain/Loss	Medium	SQL
1394	Find Lucky Integer in an Array	Easy	Python
1407	Top Travellers	Easy	SQL
1408	String Matching in an Array	Easy	Python
1431	Kids With the Greatest Number of Candies	Easy	Python
1436	Destination City	Easy	Python
1437	Check If All 1's Are at Least Length K Places Away	Easy	Python
1446	Consecutive Characters	Easy	Python
1450	Number of Students Doing Homework at a Given Time	Easy	Python
1455	Check If a Word Occurs As a Prefix of Any Word in a Sentence	Easy	Python
1461	Check If a String Contains All Binary Codes of Size K	Medium	Python
1464	Maximum Product of Two Elements in an Array	Easy	Python
1470	Shuffle the Array	Easy	Python
1472	Design Browser History	Medium	Python
1475	Final Prices With a Special Discount in a Shop	Easy	Python
1476	Subrectangle Queries	Medium	Python
1480	Running Sum of 1d Array	Easy	Python
1484	Group Sold Products By The Date	Easy	SQL
1486	XOR Operation in an Array	Easy	Python
1491	Average Salary Excluding the Minimum and Maximum Salary	Easy	Python
1502	Can Make Arithmetic Progression From Sequence	Easy	Python
1507	Reformat Date	Easy	Python
1512	Number of Good Pairs	Easy	Python
1523	Count Odd Numbers in an Interval Range	Easy	Python
1527	Patients With a Condition	Easy	SQL
1528	Shuffle String	Easy	Python
1534	Count Good Triplets	Easy	Python
1539	Kth Missing Positive Number	Easy	Python
1550	Three Consecutive Odds	Easy	Python
1572	Matrix Diagonal Sum	Easy	Python
1576	Replace All ?'s to Avoid Consecutive Repeating Characters	Easy	Python
1581	Customer Who Visited but Did Not Make Any Transactions	Easy	SQL
1582	Special Positions in a Binary Matrix	Easy	Python
1587	Bank Account Summary II	Easy	SQL
1588	Sum of All Odd Length Subarrays	Easy	Python
1603	Design Parking System	Easy	Python
1608	Special Array With X Elements Greater Than or Equal X	Easy	Python
1614	Maximum Nesting Depth of the Parentheses	Easy	Python
1619	Mean of Array After Removing Some Elements	Easy	Python
1636	Sort Array by Increasing Frequency	Easy	Python
1646	Get Maximum in Generated Array	Easy	Python
1662	Check If Two String Arrays are Equivalent	Easy	Python
1667	Fix Names in a Table	Easy	SQL
1672	Richest Customer Wealth	Easy	Python
1678	Goal Parser Interpretation	Easy	Python
1684	Count the Number of Consistent Strings	Easy	Python
1688	Count of Matches in Tournament	Easy	Python
1689	Partitioning Into Minimum Number Of Deci-Binary Numbers	Medium	Python
1693	Daily Leads and Partners	Easy	SQL
1704	Determine if String Halves Are Alike	Easy	Python
1716	Calculate Money in Leetcode Bank	Easy	Python
1720	Decode XORed Array	Easy	Python
1729	Find Followers Count	Easy	SQL
1732	Find the Highest Altitude	Easy	Python
1741	Find Total Time Spent by Each Employee	Easy	SQL
1748	Sum of Unique Elements	Easy	Python
1757	Recyclable and Low Fat Products	Easy	SQL
1768	Merge Strings Alternately	Easy	Python
1773	Count Items Matching a Rule	Easy	Python
1779	Find Nearest Point That Has the Same X or Y Coordinate	Easy	Python
1790	Check if One String Swap Can Make Strings Equal	Easy	Python
1791	Find Center of Star Graph	Easy	Python
1795	Rearrange Products Table	Easy	SQL
1796	Second Largest Digit in a String	Easy	Python
1805	Number of Different Integers in a String	Easy	Python
1812	Determine Color of a Chessboard Square	Easy	Python
1816	Truncate Sentence	Easy	Python
1817	Finding the Users Active Minutes	Medium	Python
1822	Sign of the Product of an Array	Easy	Python
1828	Queries on Number of Points Inside a Circle	Medium	Python
1832	Check if the Sentence Is Pangram	Easy	Python
1844	Replace All Digits with Characters	Easy	Python
1859	Sorting the Sentence	Easy	Python
1863	Sum of All Subset XOR Totals	Easy	Python
1873	Calculate Special Bonus	Easy	SQL
1876	Substrings of Size Three with Distinct Characters	Easy	Python
1880	Check if Word Equals Summation of Two Words	Easy	Python
1890	The Latest Login in 2020	Easy	SQL
1909	Remove One Element to Make the Array Strictly Increasing	Easy	Python
1910	Remove All Occurrences of a Substring	Medium	Python
1913	Maximum Product Difference Between Two Pairs	Easy	Python
1920	Build Array from Permutation	Easy	Python
1925	Count Square Sum Triples	Easy	Python
1929	Concatenation of Array	Easy	Python
1941	Check if All Characters Have Equal Number of Occurrences	Easy	Python
1965	Employees With Missing Information	Easy	SQL
1967	Number of Strings That Appear as Substrings in Word	Easy	Python
1979	Find Greatest Common Divisor of Array	Easy	Python
2000	Reverse Prefix of Word	Easy	Python
2006	Count Number of Pairs With Absolute Difference K	Easy	Python
2011	Final Value of Variable After Performing Operations	Easy	Python
2032	Two Out of Three	Easy	Python
2037	Minimum Number of Moves to Seat Everyone	Easy	Python
2042	Check if Numbers Are Ascending in a Sentence	Easy	Python
2047	Number of Valid Words in a Sentence	Easy	Python
2053	Kth Distinct String in an Array	Easy	Python
2057	Smallest Index With Equal Value	Easy	Python
2079	Watering Plants	Medium	Python
2085	Count Common Words With One Occurrence	Easy	Python
2094	Finding 3-Digit Even Numbers	Easy	Python
2103	Rings and Rods	Easy	Python
2108	Find First Palindromic String in the Array	Easy	Python
2114	Maximum Number of Words Found in Sentences	Easy	Python
2119	A Number After a Double Reversal	Easy	Python
2124	Check if All A's Appears Before All B's	Easy	Python
2129	Capitalize the Title	Easy	Python
2133	Check if Every Row and Column Contains All Numbers	Easy	Python
2138	Divide a String Into Groups of Size k	Easy	Python
2148	Count Elements With Strictly Smaller and Greater Elements	Easy	Python
2149	Rearrange Array Elements by Sign	Medium	Python
2154	Keep Multiplying Found Values by Two	Easy	Python
2160	Minimum Sum of Four Digit Number After Splitting Digits	Easy	Python
2161	Partition Array According to Given Pivot	Medium	Python
2169	Count Operations to Obtain Zero	Easy	Python
2176	Count Equal and Divisible Pairs in an Array	Easy	Python
2180	Count Integers With Even Digit Sum	Easy	Python
2185	Counting Words With a Given Prefix	Easy	Python
2190	Most Frequent Number Following Key In an Array	Easy	Python
2194	Cells in a Range on an Excel Sheet	Easy	Python
2200	Find All K-Distant Indices in an Array	Easy	Python
2206	Divide Array Into Equal Pairs	Easy	Python
2215	Find the Difference of Two Arrays	Easy	Python
2221	Find Triangular Sum of an Array	Medium	Python
2235	Add Two Integers	Easy	Python
2236	Root Equals Sum of Children	Easy	Python
2239	Find Closest Number to Zero	Easy	Python
2243	Calculate Digit Sum of a String	Easy	Python
2248	Intersection of Multiple Arrays	Easy	Python
2255	Count Prefixes of a Given String	Easy	Python
2264	Largest 3-Same-Digit Number in String	Easy	Python
2269	Find the K-Beauty of a Number	Easy	Python
2273	Find Resultant Array After Removing Anagrams	Easy	Python
2278	Percentage of Letter in String	Easy	Python
2283	Check if Number Has Equal Digit Count and Digit Value	Easy	Python
2299	Strong Password Checker II	Easy	Python
2303	Calculate Amount Paid in Taxes	Easy	Python
2309	Greatest English Letter in Upper and Lower Case	Easy	Python
2315	Count Asterisks	Easy	Python
2319	Check if Matrix Is X-Matrix	Easy	Python
2325	Decode the Message	Easy	Python
2331	Evaluate Boolean Binary Tree	Easy	Python
2335	Minimum Amount of Time to Fill Cups	Easy	Python
2341	Maximum Number of Pairs in Array	Easy	Python
2347	Best Poker Hand	Easy	Python
2351	First Letter to Appear Twice	Easy	Python
2352	Equal Row and Column Pairs	Medium	Python
2357	Make Array Zero by Subtracting Equal Amounts	Easy	Python
2363	Merge Similar Items	Easy	Python
2367	Number of Arithmetic Triplets	Easy	Python
2396	Strictly Palindromic Number	Medium	Python
2404	Most Frequent Even Element	Easy	Python
2413	Smallest Even Multiple	Easy	Python
2442	Count Number of Distinct Integers After Reverse Operations	Medium	Python
2469	Convert the Temperature	Easy	Python
2535	Difference Between Element Sum and Digit Sum of an Array	Easy	Python