LeetCode

602 problems solved — 553 Python · 55 SQL · 2 sh

Easy 443 · Medium 154 · Hard 5

Solutions to LeetCode problems, one directory per problem holding the statement, the solution, and — where a problem taught me something — a note on the idea that cracked it.

The table below is the part worth reading: not the code, but the one-line reason each solution works. The full index is at the bottom.

Approach notes

#	Title	Solution	Topic	Basic Idea
1	Two Sum	Python	Array, Hash Table	HashTable: While scanning through the array, wait for the target - x using hash map
15	3Sum	Python	Two Pointers, Sorting	4 Cases exist: [0,0,0], [0,p,-p], [p1,p2,-(p1+p2)], [n1, n2, -(n1+n2)]
22	Generate Parentheses	Python	DP, Backtracking, Stack	Stack: stack=[("(", l, r)]
45	Jump Game II	Python	DP, Greedy	DP: O(n^2), Greedy: (TBD)
46	Permutations	Python	Backtracking	Backtrack: Add nums[i] -> Go next -> Pop nums[i] with visited flag
55	Jump Game	Python	DP, Greedy	Greedy: (Forward) if cur position > max position then False (Backward) if last position can reach the first index then True
62	Unique Paths	Python	Combinatorics, DP	Combinatorics: (m+n-2)C(m-1), DP: dp[i][j]=dp[i-1][j]+dp[i][j-1]
70	Climbing Stairs	Python	DP, Math	DP: dp[i]=dp[i-1]+dp[i-2] where dp[0]=1
71	Simplify Path	Python	String, Stack	Stack: .. (pop), . or empty (ignore), else (push)
77	Combinations	Python	Backtracking	Backtrack: Add i -> Go next -> Backtrack (=pop i)
78	Subsets	Python	Backtracking, Bit Manipulation	Cascading: Append nums[i] (doubling the size of previous one) Backtrack: Add nums[i] -> Go next -> Backtrack (=pop nums[i])
90	Subsets II	Python	Backtracking, Bit Manipulation	Backtrack: Same idea as #78 + set.add(tuple(sorted(list))) to remove duplicates
101	Symmetric Tree	Python	DFS, BFS, Stack	DFS(Recursive): dfs(l.l, r.r) and dfs(l.r, r.l) Stack(Iterative): Basically, mirror idea is SAME & return False when one is None or vals are different
112	Path Sum	Python	BinarySearch, DFS, BFS	BFS: (root, acc_sum) DFS: (targetSum-root.val) for left and right, recursively
113	Path Sum II	Python	DFS, BFS, Backtracking	BFS: (root, [root.val])
172	Factorial Trailing Zeroes	Python	Math	O(N): dp[i]=i//5 + dp[i//5] if i%5==0 O(logN): Add # of 5s and then # of 25s ... until it reaches N
200	Number of Islands	Python	DFS, BFS, UnionFind	DFS: dfs(x+dx, y+dy) BFS: queue=[(x,y)]
221	Maximal Square	Python	DP	DP: DP[i][j]=min(DP[i][j-1], DP[i-1][j], DP[i-1][j-1])+1
231	Power of Two	Python	Bit Manipulation	BitManipulation: (2^n) and (2^n)-1 are always complementary
287	Find the Duplicate Number	Python	Two Pointers, Binary Search, Bit Manipulation	TwoPointers:
322	Coin Change	Python	DP, BFS	DP: dp[i]=min(dp[i-coins[0]], dp[i-coins[1]], dp[i-coins[2]], ... )+1
326	Power of Three	Python	Math, NumberTheory	Math: math.log(n, 3), NumberTheory: Check max pow(3)%n
342	Power of Four	Python	Bit Manipulation, Math	Math: math.log(n, 4)
437	Path Sum III	Python	DFS, BFS	(TBD)
518	Coin Change 2	Python	DP	DP: dp[i]+=dp[i-coin] (Key idea: For-loop-coin-first-then-amount)
1051	Height Checker	Python	Sort, CountingSort	Sort: 1-Liner using zip & sort
1200	Minimum Absolute Difference	Python	Sorting	Sort and find the min with zip (arr, arr[1:])
1268	Search Suggestions System	Python	Trie, BinarySearch	BinarySearch: sort and bisect_left Trie: (TBD)
1306	Jump Game III	Python	DFS, BFS	BFS: q=[index] and A[index]=-1 DFS: return A[index]==0 or f(index+A[index]) or f(index-A[index])
1512	Number of Good Pairs	Python	HashTable, Math, Counting	Math: set and count (but it requires modification of the given array), HashTable: Frequency Table is all you need
2000	Reverse Prefix of Word	Python	TwoPointers, String	String: index and [::-1]

Recurring categories: dynamic programming, BFS, DFS, math, stack, queue, hash table, backtracking, graph.

Backtracking, as a reminder to myself, is for finding all the possible cases for a situation — the moment a problem says "return every", that is the shape to reach for.

All solutions

Generated from the repository by scripts/build_readme.py, so it cannot drift from what is actually committed.

All 602 problems

#	Problem	Difficulty	Solution	Notes
1	Two Sum	Easy	Python, Python
2	Add Two Numbers	Medium	Python, Python
3	Longest Substring Without Repeating Characters	Medium	Python, Python
4	Median Of Two Sorted Arrays	Hard	Python, Python
5	Longest Palindromic Substring	Medium	Python, Python
7	Reverse Integer	Medium	Python, Python
9	Palindrome Number	Easy	Python, Python
13	Roman To Integer	Easy	Python, Python
14	Longest Common Prefix	Easy	Python, Python
15	3Sum	Medium	Python, Python
17	Letter Combinations Of A Phone Number	Medium	Python, Python
20	Valid Parentheses	Easy	Python, Python
21	Merge Two Sorted Lists	Easy	Python, Python
22	Generate Parentheses	Medium	Python, Python
28	Find The Index Of The First Occurrence In A String	Easy	Python, Python
35	Search Insert Position	Easy	Python, Python
39	Combination Sum	Medium	Python, Python
42	Trapping Rain Water	Hard	Python, Python
45	Jump Game Ii	Medium	Python, Python, Python
46	Permutations	Medium	Python, Python
48	Rotate Image	Medium	Python, Python	notes
49	Group Anagrams	Medium	Python, Python
53	Maximum Subarray	Easy	Python, Python, Python
55	Jump Game	Medium	Python, Python, Python
58	Length Of Last Word	Easy	Python, Python
62	Unique Paths	Medium	Python, Python, Python
63	Unique Paths Ii	Medium	Python, Python, Python
64	Minimum Path Sum	Medium	Python, Python, Python
66	Plus One	Easy	Python, Python
67	Add Binary	Easy	Python, Python
69	Sqrtx	Easy	Python, Python
70	Climbing Stairs	Easy	Python, Python, Python, Python
71	Simplify Path	Medium	Python, Python
73	Set Matrix Zeroes	Medium	Python, Python
75	Sort Colors	Medium	Python, Python
77	Combinations	Medium	Python, Python
78	Subsets	Medium	Python, Python
81	Search In Rotated Sorted Array Ii	Medium	Python, Python
83	Remove Duplicates From Sorted List	Easy	Python, Python
86	Partition List	Medium	Python, Python
90	Subsets Ii	Medium	Python, Python
91	Decode Ways	Medium	Python, Python
96	Unique Binary Search Trees	Medium	Python, Python, Python
100	Same Tree	Easy	Python, Python
101	Symmetric Tree	Easy	Python, Python
102	Binary Tree Level Order Traversal	Medium	Python, Python, Python
104	Maximum Depth Of Binary Tree	Easy	Python, Python, Python
108	Convert Sorted Array To Binary Search Tree	Easy	Python, Python
109	Convert Sorted List To Binary Search Tree	Medium	Python, Python
111	Minimum Depth Of Binary Tree	Easy	Python, Python
112	Path Sum	Easy	Python, Python
113	Path Sum Ii	Medium	Python, Python
118	Pascals Triangle	Easy	Python, Python, Python, Python
119	Pascals Triangle Ii	Easy	Python, Python, Python, Python
120	Triangle	Medium	Python, Python, Python, Python
121	Best Time To Buy And Sell Stock	Easy	Python, Python, Python
122	Best Time To Buy And Sell Stock Ii	Medium	Python, Python
125	Valid Palindrome	Easy	Python, Python
129	Sum Root To Leaf Numbers	Medium	Python, Python
136	Single Number	Easy	Python, Python
137	Single Number Ii	Medium	Python, Python
152	Maximum Product Subarray	Medium	Python, Python, Python, Python
162	Find Peak Element	Medium	Python, Python
167	Two Sum Ii Input Array Is Sorted	Easy	Python, Python
169	Majority Element	Easy	Python, Python
171	Excel Sheet Column Number	Easy	Python, Python
172	Factorial Trailing Zeroes	Medium	Python, Python
175	Combine Two Tables	Easy	SQL, SQL
176	Second Highest Salary	Medium	SQL, SQL
182	Duplicate Emails	Easy	SQL, SQL
183	Customers Who Never Order	Easy	SQL, SQL
189	Rotate Array	Medium	Python, Python
191	Number Of 1 Bits	Easy	Python, Python
192	Word Frequency	Medium	sh
195	Tenth Line	Easy	sh
196	Delete Duplicate Emails	Easy	SQL, SQL
197	Rising Temperature	Easy	SQL, SQL
198	House Robber	Medium	Python, Python, Python
199	Binary Tree Right Side View	Medium	Python, Python, Python
200	Number Of Islands	Medium	Python, Python, Python
202	Happy Number	Easy	Python, Python
203	Remove Linked List Elements	Easy	Python, Python
204	Count Primes	Medium	Python, Python
205	Isomorphic Strings	Easy	Python, Python
206	Reverse Linked List	Easy	Python, Python
213	House Robber Ii	Medium	Python, Python, Python
215	Kth Largest Element In An Array	Medium	Python, Python
217	Contains Duplicate	Easy	Python, Python, Python
221	Maximal Square	Medium	Python, Python, Python
225	Implement Stack Using Queues	Easy	Python, Python
226	Invert Binary Tree	Easy	Python, Python
228	Summary Ranges	Easy	Python, Python
230	Kth Smallest Element In A Bst	Medium	Python, Python
231	Power Of Two	Easy	Python, Python, Python
232	Implement Queue Using Stacks	Easy	Python, Python
234	Palindrome Linked List	Easy	Python, Python
237	Delete Node In A Linked List	Easy	Python, Python
238	Product Of Array Except Self	Medium	Python, Python
242	Valid Anagram	Easy	Python, Python
258	Add Digits	Easy	Python, Python, Python
263	Ugly Number	Easy	Python, Python
268	Missing Number	Easy	Python, Python, Python
279	Perfect Squares	Medium	Python, Python
283	Move Zeroes	Easy	Python, Python, Python
287	Find The Duplicate Number	Medium	Python, Python
290	Word Pattern	Easy	Python, Python	notes
300	Longest Increasing Subsequence	Medium	Python, Python
303	Range Sum Query Immutable	Easy	Python, Python
318	Maximum Product Of Word Lengths	Medium	Python, Python
322	Coin Change	Medium	Python, Python, Python
326	Power Of Three	Easy	Python, Python, Python
328	Odd Even Linked List	Medium	Python, Python
329	Longest Increasing Path In A Matrix	Hard	Python, Python
334	Increasing Triplet Subsequence	Medium	Python, Python
338	Counting Bits	Easy	Python, Python
342	Power Of Four	Easy	Python, Python, Python
343	Integer Break	Medium	Python, Python
344	Reverse String	Easy	Python, Python
345	Reverse Vowels Of A String	Easy	Python, Python
347	Top K Frequent Elements	Medium	Python, Python
349	Intersection Of Two Arrays	Easy	Python, Python
350	Intersection of Two Arrays II	Easy	Python
367	Valid Perfect Square	Easy	Python, Python
371	Sum Of Two Integers	Medium	Python, Python
374	Guess Number Higher Or Lower	Easy	Python, Python
377	Combination Sum Iv	Medium	Python, Python
378	Kth Smallest Element In A Sorted Matrix	Medium	Python, Python
387	First Unique Character In A String	Easy	Python, Python
389	Find The Difference	Easy	Python, Python, Python
392	Is Subsequence	Easy	Python, Python, Python
404	Sum Of Left Leaves	Easy	Python, Python, Python
409	Longest Palindrome	Easy	Python, Python
412	Fizz Buzz	Easy	Python, Python
413	Arithmetic Slices	Medium	Python, Python
414	Third Maximum Number	Easy	Python, Python
415	Add Strings	Easy	Python, Python
434	Number Of Segments In A String	Easy	Python, Python
437	Path Sum Iii	Medium	Python, Python
441	Arranging Coins	Easy	Python, Python
451	Sort Characters By Frequency	Medium	Python, Python
459	Repeated Substring Pattern	Easy	Python, Python
461	Hamming Distance	Easy	Python, Python
476	Number Complement	Easy	Python, Python
496	Next Greater Element I	Easy	Python, Python
500	Keyboard Row	Easy	Python, Python
504	Base 7	Easy	Python, Python
509	Fibonacci Number	Easy	Python, Python
511	Game Play Analysis I	Easy	SQL
513	Find Bottom Left Tree Value	Medium	Python, Python
515	Find Largest Value In Each Tree Row	Medium	Python, Python
516	Longest Palindromic Subsequence	Medium	Python, Python
518	Coin Change Ii	Medium	Python, Python, Python
520	Detect Capital	Easy	Python, Python
530	Minimum Absolute Difference In Bst	Easy	Python, Python
535	Encode And Decode Tinyurl	Medium	Python, Python	notes
537	Complex Number Multiplication	Medium	Python, Python
539	Minimum Time Difference	Medium	Python, Python
547	Number Of Provinces	Medium	Python, Python
557	Reverse Words In A String Iii	Easy	Python, Python
559	Maximum Depth of N-ary Tree	Easy	Python
561	Array Partition	Easy	Python, Python
566	Reshape The Matrix	Easy	Python, Python
583	Delete Operation For Two Strings	Medium	Python, Python
584	Find Customer Referee	Easy	SQL, SQL
586	Customer Placing The Largest Number Of Orders	Easy	SQL
589	N-ary Tree Preorder Traversal	Easy	Python
594	Longest Harmonious Subsequence	Easy	Python, Python
595	Big Countries	Easy	SQL, SQL
599	Minimum Index Sum Of Two Lists	Easy	Python, Python
607	Sales Person	Easy	SQL, SQL
608	Tree Node	Medium	SQL, SQL
620	Not Boring Movies	Easy	SQL, SQL
627	Swap Sex Of Employees	Easy	SQL, SQL
637	Average Of Levels In Binary Tree	Easy	Python, Python
653	Two Sum Iv Input Is A Bst	Easy	Python, Python
657	Robot Return To Origin	Easy	Python, Python
682	Baseball Game	Easy	Python, Python
695	Max Area Of Island	Medium	Python, Python, Python
697	Degree Of An Array	Easy	Python, Python
700	Search in a Binary Search Tree	Easy	Python
704	Binary Search	Easy	Python, Python
709	To Lower Case	Easy	Python
724	Find Pivot Index	Easy	Python, Python
728	Self Dividing Numbers	Easy	Python, Python
739	Daily Temperatures	Medium	Python, Python
742	To Lower Case	Easy	Python
746	Min Cost Climbing Stairs	Easy	Python, Python
747	Min Cost Climbing Stairs	Easy	Python
766	Toeplitz Matrix	Easy	Python
771	Jewels and Stones	Easy	Python
774	Maximum Depth of N-ary Tree	Easy	Python
775	N-ary Tree Preorder Traversal	Easy	Python
777	Toeplitz Matrix	Easy	Python
782	Jewels and Stones	Easy	Python
783	Search In A Binary Search Tree	Easy	Python, Python
792	Binary Search	Easy	Python
796	Rotate String	Easy	Python
799	Minimum Distance Between BST Nodes	Easy	Python
804	Unique Morse Code Words	Easy	Python
812	Rotate String	Easy	Python
822	Unique Morse Code Words	Easy	Python
832	Flipping an Image	Easy	Python
844	Backspace String Compare	Easy	Python
852	Peak Index in a Mountain Array	Easy	Python
856	Score of Parentheses	Medium	Python
861	Flipping an Image	Easy	Python
867	Transpose Matrix	Easy	Python
868	Binary Gap	Easy	Python
874	Backspace String Compare	Easy	Python
876	Middle of the Linked List	Easy	Python
882	Peak Index in a Mountain Array	Medium	Python
884	Uncommon Words from Two Sentences	Easy	Python
886	Score of Parentheses	Medium	Python
890	Find and Replace Pattern	Medium	Python
898	Transpose Matrix	Easy	Python
899	Binary Gap	Easy	Python
905	Sort Array By Parity	Easy	Python
908	Middle Of The Linked List	Easy	Python, Python
916	Word Subsets	Medium	Python
920	Uncommon Words from Two Sentences	Easy	Python
922	Sort Array By Parity II	Easy	Python
926	Find and Replace Pattern	Medium	Python
931	Minimum Falling Path Sum	Medium	Python, Python
938	Range Sum of BST	Easy	Python
941	Sort Array By Parity	Easy	Python
942	DI String Match	Easy	Python
944	Smallest Range I	Easy	Python
952	Word Subsets	Medium	Python
953	Verifying an Alien Dictionary	Easy	Python
958	Sort Array By Parity II	Easy	Python
961	N-Repeated Element in Size 2N Array	Easy	Python
965	Univalued Binary Tree	Easy	Python
967	Minimum Falling Path Sum	Medium	Python
975	Range Sum of BST	Easy	Python
976	Largest Perimeter Triangle	Easy	Python, Python
977	Squares of a Sorted Array	Easy	Python
979	DI String Match	Easy	Python
983	Minimum Cost For Tickets	Medium	Python
988	Smallest String Starting From Leaf	Medium	Python
990	Verifying an Alien Dictionary	Easy	Python
993	Cousins in Binary Tree	Easy	Python
1001	N-Repeated Element in Size 2N Array	Easy	Python
1002	Find Common Characters	Easy	Python
1005	Univalued Binary Tree	Easy	Python
1009	Complement of Base 10 Integer	Easy	Python
1013	Fibonacci Number	Easy	Python
1014	Best Sightseeing Pair	Medium	Python
1018	Binary Prefix Divisible By 5	Easy	Python, Python
1019	Squares of a Sorted Array	Easy	Python
1021	Remove Outermost Parentheses	Easy	Python
1022	Sum of Root To Leaf Binary Numbers	Easy	Python
1025	Minimum Cost For Tickets	Medium	Python
1029	Two City Scheduling	Medium	Python	notes
1030	Smallest String Starting From Leaf	Medium	Python
1035	Cousins in Binary Tree	Easy	Python
1043	Partition Array for Maximum Sum	Medium	Python
1044	Find Common Characters	Easy	Python
1046	Last Stone Weight	Easy	Python
1050	Actors and Directors Who Cooperated At Least Three Times	Easy	SQL
1051	Height Checker	Easy	Python
1054	Complement of Base 10 Integer	Easy	Python
1063	Best Sightseeing Pair	Medium	Python
1071	Binary Prefix Divisible By 5	Easy	Python
1078	Remove Outermost Parentheses	Easy	Python
1079	Sum of Root To Leaf Binary Numbers	Easy	Python
1084	Sales Analysis III	Easy	SQL
1091	Shortest Path in Binary Matrix	Medium	Python
1095	Two City Scheduling	Medium	Python
1108	Defanging an IP Address	Easy	Python
1112	Find Words That Can Be Formed by Characters	Easy	Python
1116	Maximum Level Sum of a Binary Tree	Medium	Python
1121	Partition Array for Maximum Sum	Medium	Python
1122	Relative Sort Array	Easy	Python	notes
1127	Last Stone Weight	Easy	Python
1136	Actors and Directors Who Cooperated At Least Three Times	Easy	SQL
1137	Height Checker	Easy	Python, Python, Python
1141	User Activity for the Past 30 Days I	Easy	SQL
1143	Longest Common Subsequence	Medium	Python
1148	Article Views I	Easy	SQL
1158	Market Analysis I	Medium	SQL
1160	Find Words That Can Be Formed by Characters	Easy	Python
1161	Maximum Level Sum of a Binary Tree	Medium	Python
1171	Shortest Path in Binary Matrix	Medium	Python
1174	Sales Analysis III	Easy	SQL
1179	Game Play Analysis I	Easy	SQL
1200	Minimum Absolute Difference	Easy	Python
1205	Defanging an IP Address	Easy	Python
1207	Unique Number of Occurrences	Easy	Python
1217	Relative Sort Array	Easy	Python
1221	Split a String in Balanced Strings	Easy	Python
1231	Replace Elements with Greatest Element on Right Side	Easy	Python
1232	Check If It Is a Straight Line	Easy	Python
1236	N-th Tribonacci Number	Easy	Python
1241	Decompress Run-Length Encoded List	Easy	Python
1245	User Activity for the Past 30 Days I	Easy	SQL
1250	Longest Common Subsequence	Medium	Python
1252	Cells with Odd Values in a Matrix	Easy	Python
1254	Deepest Leaves Sum	Medium	Python, Python
1258	Article Views I	Easy	SQL
1264	Maximum Number of Words You Can Type	Easy	Python
1266	Minimum Time Visiting All Points	Easy	Python
1268	Market Analysis I	Medium	SQL, Python
1277	Count Square Submatrices with All Ones	Medium	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
1290	Convert Binary Number in a Linked List to Integer	Easy	Python
1293	Three Consecutive Odds	Easy	Python
1295	Find Numbers with Even Number of Digits	Easy	Python
1299	Replace Elements with Greatest Element on Right Side	Easy	Python
1302	Deepest Leaves Sum	Medium	Python
1304	Find N Unique Integers Sum up to Zero	Easy	Python	notes
1306	Jump Game III	Medium	Python, Python, Python
1309	Decrypt String from Alphabet to Integer Mapping	Easy	Python
1313	Decompress Run-Length Encoded List	Easy	Python
1319	Unique Number of Occurrences	Easy	Python
1323	Maximum 69 Number	Easy	Python
1337	The K Weakest Rows in a Matrix	Easy	Python	notes
1341	Split a String in Balanced Strings	Easy	Python
1342	Number of Steps to Reduce a Number to Zero	Easy	Python
1349	Check If It Is a Straight Line	Easy	Python
1351	Count Negative Numbers in a Sorted Matrix	Easy	Python
1356	Sort Integers by The Number of 1 Bits	Easy	Python
1363	Greatest English Letter in Upper and Lower Case	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
1378	Cells with Odd Values in a Matrix	Easy	Python
1380	Lucky Numbers in a Matrix	Easy	Python, Python
1385	Find the Distance Value Between Two Arrays	Easy	Python
1389	Create Target Array in the Given Order	Easy	Python
1392	Find the Difference of Two Arrays	Easy	Python
1393	Capital Gain/Loss	Medium	SQL
1395	Minimum Time Visiting All Points	Easy	Python
1397	Search Suggestions System	Medium	Python
1399	Count Largest Group	Easy	Python
1402	Count Square Submatrices with All Ones	Medium	Python
1406	Subtract the Product and Sum of Digits of an Integer	Easy	Python
1407	Group The People Given The Group Size They Belong To	Easy	Python, SQL
1411	Convert Binary Number in a Linked List to Integer	Easy	Python
1421	Find Numbers with Even Number of Digits	Easy	Python
1426	Find N Unique Integers Sum up to Zero	Easy	Python
1428	Jump Game III	Medium	Python
1430	Find the K-Beauty of a Number	Easy	Python
1431	Kids With the Greatest Number of Candies	Easy	Python
1434	Decrypt String from Alphabet to Integer Mapping	Easy	Python
1436	Destination City	Easy	Python
1441	Build an Array With Stack Operations	Easy	Python
1444	Number of Steps to Reduce a Number to Zero	Easy	Python
1446	Consecutive Characters	Easy	Python
1448	Count Good Nodes in Binary Tree	Medium	Python, 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
1458	Sort Integers by The Number of 1 Bits	Easy	Python
1461	Check If a String Contains All Binary Codes of Size K	Medium	Python
1463	The K Weakest Rows in a Matrix	Easy	Python
1464	Maximum Product of Two Elements in an Array	Easy	Python
1470	Shuffle the Array	Easy	Python
1475	Final Prices With a Special Discount in a Shop	Easy	Python
1476	Count Negative Numbers in a Sorted Matrix	Easy	Python
1480	Running Sum of 1d Array	Easy	Python
1482	How Many Numbers Are Smaller Than the Current Number	Easy	Python
1484	Group Sold Products By The Date	Easy	SQL
1486	Find the Distance Value Between Two Arrays	Easy	Python
1490	Generate a String With Characters That Have Odd Counts	Easy	Python
1491	Average Salary Excluding the Minimum and Maximum Salary	Easy	Python
1496	Lucky Numbers in a Matrix	Easy	Python
1500	Count Largest Group	Easy	Python
1502	Can Make Arithmetic Progression From Sequence	Easy	Python
1505	Create Target Array in the Given Order	Easy	Python
1509	Minimum Difference Between Largest and Smallest Value in Three Moves	Medium	Python
1512	Number of Good Pairs	Easy	Python
1523	Capital Gainloss	Easy	SQL, Python
1525	Number of Good Ways to Split a String	Medium	Python
1527	Patients With a Condition	Easy	SQL
1528	Kids With The Greatest Number Of Candies	Easy	Python, Python
1541	Top Travellers	Easy	SQL
1542	Consecutive Characters	Easy	Python
1544	Count Good Nodes in Binary Tree	Medium	Python
1547	Destination City	Easy	Python
1550	Three Consecutive Odds	Easy	Python
1551	Minimum Operations to Make Array Equal	Medium	Python
1552	Build an Array With Stack Operations	Medium	Python
1557	Check If a String Contains All Binary Codes of Size K	Medium	Python
1560	Number of Students Doing Homework at a Given Time	Easy	Python
1566	Check If a Word Occurs As a Prefix of Any Word in a Sentence	Easy	Python
1567	Maximum Length of Subarray With Positive Product	Medium	Python
1570	Final Prices With a Special Discount in a Shop	Easy	Python
1572	Matrix Diagonal Sum	Easy	Python
1574	Maximum Product of Two Elements in an Array	Easy	Python
1578	Minimum Time to Make Rope Colorful	Medium	Python
1580	Shuffle the Array	Easy	Python
1581	Customer Who Visited but Did Not Make Any Transactions	Easy	SQL
1584	Average Salary Excluding the Minimum and Maximum Salary	Easy	Python
1587	Bank Account Summary II	Easy	SQL
1588	Sum of All Odd Length Subarrays	Easy	Python
1603	Design Parking System	Easy	Python, Python
1605	Find Valid Matrix Given Row and Column Sums	Medium	Python
1609	Even Odd Tree	Medium	Python	notes
1616	Minimum Difference Between Largest and Smallest Value in Three Moves	Medium	Python
1625	Group Sold Products By The Date	Easy	SQL
1626	Can Make Arithmetic Progression From Sequence	Easy	Python
1630	Count Odd Numbers in an Interval Range	Easy	Python
1632	Number of Good Ways to Split a String	Medium	Python
1635	Number of Good Pairs	Easy	Python
1636	Sort Array by Increasing Frequency	Easy	Python
1641	Count Sorted Vowel Strings	Medium	Python
1646	Get Maximum in Generated Array	Easy	Python
1651	Shuffle String	Easy	Python
1662	Check If Two String Arrays are Equivalent	Easy	Python
1667	Fix Names in a Table	Easy	SQL
1670	Patients With a Condition	Easy	SQL
1672	Richest Customer Wealth	Easy	Python
1674	Minimum Operations to Make Array Equal	Medium	Python
1677	Matrix Diagonal Sum	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
1690	Maximum Length of Subarray With Positive Product	Medium	Python
1693	Daily Leads and Partners	Easy	SQL, Python
1700	Minimum Time to Make Rope Colorful	Medium	Python
1704	Determine if String Halves Are Alike	Easy	Python
1708	Design Parking System	Easy	Python
1711	Find Valid Matrix Given Row and Column Sums	Medium	Python
1724	Customer Who Visited but Did Not Make Any Transactions	Easy	SQL
1729	Find Followers Count	Easy	SQL
1731	Even Odd Tree	Medium	Python
1734	Bank Account Summary II	Easy	SQL
1741	Find Total Time Spent by Each Employee	Easy	SQL, Python
1742	Maximum Number of Balls in a Box	Easy	Python
1748	Sum of Unique Elements	Easy	Python
1757	Recyclable and Low Fat Products	Easy	SQL
1761	Count Sorted Vowel Strings	Medium	Python
1768	Merge Strings Alternately	Easy	Python
1769	Get Maximum in Generated Array	Easy	Python
1773	Count Items Matching a Rule	Easy	Python
1779	Find Nearest Point That Has the Same X or Y Coordinate	Easy	Python
1781	Check If Two String Arrays are Equivalent	Easy	Python
1786	Count the Number of Consistent Strings	Easy	Python
1790	Check if One String Swap Can Make Strings Equal	Easy	Python
1791	Richest Customer Wealth	Easy	Python
1795	Rearrange Products Table	Easy	SQL
1797	Goal Parser Interpretation	Easy	Python
1806	Count of Matches in Tournament	Easy	Python
1811	Fix Names in a Table	Easy	SQL
1812	Determine Color of a Chessboard Square	Easy	Python
1816	Truncate Sentence	Easy	Python
1822	Sign of the Product of an Array	Easy	Python
1823	Determine if String Halves Are Alike	Easy	Python
1832	Check if the Sentence Is Pangram	Easy	Python
1833	Find the Highest Altitude	Easy	Python
1837	Daily Leads And Partners	Easy	SQL, Python
1844	Maximum Number Of Balls In A Box	Easy	Python, Python
1848	Sum of Unique Elements	Easy	Python
1859	Sorting the Sentence	Easy	Python
1873	Calculate Special Bonus	Easy	SQL
1876	Substrings of Size Three with Distinct Characters	Easy	Python
1877	Find Followers Count	Medium	SQL, Python
1880	Check if Word Equals Summation of Two Words	Easy	Python
1888	Find Nearest Point That Has the Same X or Y Coordinate	Easy	Python
1890	The Latest Login in 2020	Easy	SQL
1892	Find Total Time Spent by Each Employee	Easy	SQL
1894	Merge Strings Alternately	Easy	Python
1899	Count Items Matching a Rule	Easy	Python
1908	Recyclable and Low Fat Products	Easy	SQL
1913	Maximum Product Difference Between Two Pairs	Easy	Python
1915	Check if One String Swap Can Make Strings Equal	Easy	Python
1920	Build Array from Permutation	Easy	Python, Python
1925	Count Square Sum Triples	Easy	Python
1929	Concatenation of Array	Easy	Python
1935	Maximum Number of Words You Can Type	Easy	Python
1941	Check if All Characters Have Equal Number of Occurrences	Easy	Python
1944	Truncate Sentence	Easy	Python
1948	Rearrange Products Table	Easy	SQL
1950	Sign of the Product of an Array	Easy	Python
1954	Replace All Digits with Characters	Easy	Python
1960	Check if the Sentence Is Pangram	Easy	Python
1965	Employees With Missing Information	Easy	SQL, Python
1967	Number of Strings That Appear as Substrings in Word	Easy	Python
1970	Sorting the Sentence	Easy	Python
1979	Find Greatest Common Divisor of Array	Easy	Python
1987	Substrings of Size Three with Distinct Characters	Easy	Python
1988	Minimize Maximum Pair Sum in Array	Medium	Python
2000	Reverse Prefix of Word	Easy	Python
2006	Count Number of Pairs With Absolute Difference K	Easy	Python
2010	Check if Word Equals Summation of Two Words	Easy	Python
2011	Final Value of Variable After Performing Operations	Easy	Python
2016	Maximum Difference Between Increasing Elements	Easy	Python
2023	Number of Pairs of Strings With Concatenation Equal to Target	Medium	Python
2024	Calculate Special Bonus	Easy	SQL
2032	Two Out of Three	Easy	Python
2037	Count Square Sum Triples	Easy	Python
2041	The Latest Login in 2020	Easy	SQL
2042	Check if Numbers Are Ascending in a Sentence	Easy	Python, Python
2048	Build Array from Permutation	Easy	Python
2053	Check If All Characters Have Equal Number Of Occurrences	Easy	Python, Python
2057	Smallest Index With Equal Value	Easy	Python
2058	Concatenation of Array	Easy	Python
2062	Count Vowel Substrings of a String	Easy	Python
2073	Time Needed to Buy Tickets	Easy	Python
2078	Two Furthest Houses With Different Colors	Easy	Python
2085	Count Common Words With One Occurrence	Easy	Python
2089	Find Target Indices After Sorting Array	Easy	Python
2099	Number of Strings That Appear as Substrings in Word	Easy	Python
2106	Find Greatest Common Divisor of Array	Easy	Python
2108	Find First Palindromic String in the Array	Easy	Python
2110	Employees With Missing Information	Easy	SQL
2114	Maximum Number of Words Found in Sentences	Easy	Python
2116	Count Number of Pairs With Absolute Difference K	Easy	Python
2119	A Number After a Double Reversal	Easy	Python
2124	Check if All A's Appears Before All B's	Easy	Python
2128	Reverse Prefix of Word	Easy	Python
2129	Capitalize the Title	Easy	Python
2133	Check if Every Row and Column Contains All Numbers	Easy	Python, Python
2137	Final Value of Variable After Performing Operations	Easy	Python
2144	Maximum Difference Between Increasing Elements	Easy	Python
2154	Keep Multiplying Found Values by Two	Easy	Python
2159	Two Out of Three	Easy	Python
2160	Minimum Sum of Four Digit Number After Splitting Digits	Easy	Python	notes
2163	Kth Distinct String in an Array	Easy	Python
2164	Sort Even and Odd Indices Independently	Easy	Python	notes
2168	Check if Numbers Are Ascending in a Sentence	Easy	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
2181	Merge Nodes in Between Zeros	Medium	Python, Python
2185	Counting Words With a Given Prefix	Easy	Python
2186	Count Vowel Substrings of a String	Easy	Python
2190	Count Common Words With One Occurrence	Easy	Python
2194	Cells in a Range on an Excel Sheet	Easy	Python
2195	Time Needed to Buy Tickets	Easy	Python
2199	Two Furthest Houses With Different Colors	Easy	Python
2206	Divide Array Into Equal Pairs	Easy	Python
2210	Find Target Indices After Sorting Array	Easy	Python
2215	Find the Difference of Two Arrays	Easy	Python
2219	Maximum Number of Words Found in Sentences	Easy	Python
2220	Minimum Bit Flips to Convert Number	Easy	Python
2221	Find Triangular Sum of an Array	Medium	Python
2231	Find First Palindromic String in the Array	Easy	Python
2235	Add Two Integers	Easy	Python, Python
2236	Root Equals Sum of Children	Easy	Python
2238	A Number After a Double Reversal	Easy	Python
2243	Check if All A's Appears Before All B's	Easy	Python
2248	Intersection of Multiple Arrays	Easy	Python
2254	Check if Every Row and Column Contains All Numbers	Easy	Python
2255	Count Prefixes of a Given String	Easy	Python
2264	Largest 3-Same-Digit Number in String	Easy	Python, Python
2265	Count Nodes Equal to Average of Subtree	Medium	Python
2266	Count Number of Texts	Medium	Python
2267	Check if There Is a Valid Parentheses String Path	Hard	Python
2269	Find the K-Beauty of a Number	Easy	Python
2270	Number of Ways to Split Array	Medium	Python
2274	Keep Multiplying Found Values by Two	Easy	Python
2277	Count Equal and Divisible Pairs in an Array	Easy	Python
2278	Percentage of Letter in String	Easy	Python
2283	Check if Number Has Equal Digit Count and Digit Value	Easy	Python, Python
2284	Sender With Largest Word Count	Medium	Python
2285	Maximum Total Importance of Roads	Medium	Python
2288	Count Operations to Obtain Zero	Easy	Python
2292	Counting Words With a Given Prefix	Easy	Python
2298	Count Integers With Even Digit Sum	Easy	Python
2299	Merge Nodes In Between Zeros	Easy	Python, Python
2304	Cells in a Range on an Excel Sheet	Easy	Python
2308	Divide Array Into Equal Pairs	Easy	Python
2309	Greatest English Letter in Upper and Lower Case	Easy	Python
2323	Minimum Bit Flips to Convert Number	Easy	Python
2324	Find Triangular Sum of an Array	Medium	Python
2325	Decode the Message	Easy	Python
2331	Intersection of Multiple Arrays	Easy	Python
2341	Count Prefixes Of A Given String	Easy	Python, Python
2346	Largest 3-Same-Digit Number in String	Easy	Python
2347	Count Nodes Equal to Average of Subtree	Medium	Python
2348	Count Number of Texts	Medium	Python
2349	Check if There Is a Valid Parentheses String Path	Hard	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
2358	Number of Ways to Split Array	Medium	Python
2363	Merge Similar Items	Easy	Python
2365	Percentage of Letter in String	Easy	Python
2367	Number of Arithmetic Triplets	Easy	Python
2377	Check if Number Has Equal Digit Count and Digit Value	Easy	Python
2378	Sender With Largest Word Count	Medium	Python
2379	Maximum Total Importance of Roads	Medium	Python
2383	Add Two Integers	Easy	Python
2384	Root Equals Sum of Children	Easy	Python
2391	Strong Password Checker II	Easy	Python
2396	Strictly Palindromic Number	Medium	Python
2405	Optimal Partition of String	Medium	Python
2406	Decode the Message	Easy	Python
2413	Smallest Even Multiple	Easy	Python
2418	Sort the People	Easy	Python
2421	Maximum Number of Pairs in Array	Easy	Python
2427	First Letter To Appear Twice	Easy	Python, Python
2428	Equal Row and Column Pairs	Medium	Python
2436	Make Array Zero by Subtracting Equal Amounts	Easy	Python
2442	Number of Arithmetic Triplets	Easy	Python
2447	Merge Similar Items	Easy	Python
2481	Strictly Palindromic Number	Medium	Python
2487	Optimal Partition of String	Medium	Python
2491	Smallest Even Multiple	Easy	Python
2502	Sort the People	Easy	Python
2507	Number of Common Factors	Easy	Python
2556	Convert the Temperature	Easy	Python

Reference

• LeetHub: Linking GitHub and LeetCode — what syncs the statements into this repo