leetcode

My LeetCode submissions

• Easy: 121 / 847
• Medium: 98 / 1777
• Hard: 9 / 786

Index

C++

No.	Difficulty	Title	Code	Time complexity	Space complexity
1	Easy	Two Sum	1-two-sum.cpp	O(n)	O(n)
2	Medium	Add Two Numbers	2-add-two-numbers.cpp	O(n1+n2)	O(n1+n2)
3	Medium	Longest Substring Without Repeating Characters	3-longest-substring-without-repeating-characters.cpp	O(n)	O(n)
5	Medium	Longest Palindromic Substring	5-longest-palindromic-substring.cpp	O(n^2)	O(n)
6	Medium	Zigzag Conversion	6-zigzag-conversion.cpp	O(n)	O(n)
8	Medium	String to Integer (atoi)	8-string-to-integer-atoi.cpp	O(n)	O(1)
9	Easy	Palindrome Number	9-palindrome-number.cpp	O(1)	O(1)
19	Medium	Remove Nth Node From End of List	19-remove-nth-node-from-end-of-list.cpp	O(n)	O(1)
20	Easy	Valid Parentheses	20-valid-parentheses.cpp	O(n)	O(n)
21	Easy	Merge Two Sorted Lists	21-merge-two-sorted-lists.cpp	O(min(n1, n2))	O(1)
22	Medium	Generate Parentheses	22-generate-parentheses.cpp	O(C(n)), where C(n) = the n-th Catalan number	O(C(n)), where C(n) = the n-th Catalan number
23	Hard	Merge k Sorted Lists	23-merge-k-sorted-lists.cpp	O(n*log(k))	O(k)
28	Easy	Find the Index of the First Occurrence in a String	28-find-the-index-of-the-first-occurrence-in-a-string.cpp	O(m+n)	O(m)
31	Medium	Next Permutation	31-next-permutation.cpp	O(n)	O(1)
33	Medium	Search in Rotated Sorted Array	33-search-in-rotated-sorted-array.cpp	O(log(n))	O(log(n))
35	Easy	Search Insert Position	35-search-insert-position.cpp	O(log(n))	O(1)
39	Medium	Combination Sum	39-combination-sum.cpp	O(2^(n+t)*t)	O(2^(n+t)*t)
46	Medium	Permutations	46-permutations.cpp	O(n*n!)	O(n*n!)
48	Medium	Rotate Image	48-rotate-image.cpp	O(n^2)	O(1)
49	Medium	Group Anagrams	49-group-anagrams.cpp	O(n*m*log(m))	O(n*m)
50	Medium	Pow(x, n)	50-powx-n.cpp	O(log(n))	O(log(n))
53	Medium	Maximum Subarray	53-maximum-subarray.cpp	O(n)	O(1)
55	Medium	Jump Game	55-jump-game.cpp	O(n)	O(1)
62	Medium	Unique Paths	62-unique-paths.cpp	O(m*n)	O(m*n)
63	Medium	Unique Paths II	63-unique-paths-ii.cpp	O(m*n)	O(m*n)
64	Medium	Minimum Path Sum	64-minimum-path-sum.cpp	O(m*n)	O(m*n)
70	Easy	Climbing Stairs	70-climbing-stairs.cpp	O(n)	O(n)
75	Medium	Sort Colors	75-sort-colors.cpp	O(n)	O(1)
76	Hard	Minimum Window Substring	76-minimum-window-substring.cpp	O(m+n)	O(m)
77	Medium	Combinations	77-combinations.cpp	O(k*C(n,k))	O(k*C(n,k))
78	Medium	Subsets	78-subsets.cpp	O(n*2^n)	O(n*2^n)
82	Medium	Remove Duplicates from Sorted List II	82-remove-duplicates-from-sorted-list-ii.cpp	O(n)	O(1)
83	Easy	Remove Duplicates from Sorted List	83-remove-duplicates-from-sorted-list.cpp	O(n)	O(1)
88	Easy	Merge Sorted Array	88-merge-sorted-array.cpp	O(m+n)	O(1)
91	Medium	Decode Ways	91-decode-ways.cpp	O(n)	O(n)
94	Easy	Binary Tree Inorder Traversal	94-binary-tree-inorder-traversal.cpp	O(n)	O(n)
95	Medium	Unique Binary Search Trees II	95-unique-binary-search-trees-ii.cpp	O(C(n)), where C(n) = the n-th Catalan number	O(C(n))
98	Medium	Validate Binary Search Tree	98-validate-binary-search-tree.cpp	O(n)	O(log(n))
102	Medium	Binary Tree Level Order Traversal	102-binary-tree-level-order-traversal.cpp	O(n)	O(n)
103	Medium	Binary Tree Zigzag Level Order Traversal	103-binary-tree-zigzag-level-order-traversal.cpp	O(n)	O(n)
104	Easy	Maximum Depth of Binary Tree	104-maximum-depth-of-binary-tree.cpp	O(n)	O(log(n))
105	Medium	Construct Binary Tree from Preorder and Inorder Traversal	105-construct-binary-tree-from-preorder-and-inorder-traversal.cpp	O(n)	O(n)
108	Easy	Convert Sorted Array to Binary Search Tree	108-convert-sorted-array-to-binary-search-tree.cpp	O(n)	O(n)
111	Easy	Minimum Depth of Binary Tree	111-minimum-depth-of-binary-tree.cpp	O(n)	O(log(n))
112	Easy	Path Sum	112-path-sum.cpp	O(n)	O(n)
113	Medium	Path Sum II	113-path-sum-ii.cpp	O(n^2)	O(n^2)
116	Medium	Populating Next Right Pointers in Each Node	116-populating-next-right-pointers-in-each-node.cpp	O(n)	O(1)
118	Easy	Pascal's Triangle	118-pascals-triangle.cpp	O(n^2)	O(n^2)
120	Medium	Triangle	120-triangle.cpp	O(n^2)	O(n^2)
121	Easy	Best Time to Buy and Sell Stock	121-best-time-to-buy-and-sell-stock.cpp	O(n)	O(1)
122	Medium	Best Time to Buy and Sell Stock II	122-best-time-to-buy-and-sell-stock-ii.cpp	O(n)	O(1)
124	Hard	Binary Tree Maximum Path Sum	124-binary-tree-maximum-path-sum.cpp	O(n)	O(n)
127	Hard	Word Ladder	127-word-ladder.cpp	O(m*n^2)	O(m*n)
136	Easy	Single Number	136-single-number.cpp	O(n)	O(1)
139	Medium	Word Break	139-word-break.cpp	O(m*n)	O(n)
141	Easy	Linked List Cycle	141-linked-list-cycle.cpp	O(n)	O(1)
142	Medium	Linked List Cycle II	142-linked-list-cycle-ii.cpp	O(n)	O(1)
144	Easy	Binary Tree Preorder Traversal	144-binary-tree-preorder-traversal.cpp	O(n)	O(n)
145	Easy	Binary Tree Postorder Traversal	145-binary-tree-postorder-traversal.cpp	O(n)	O(n)
146	Medium	LRU Cache	146-lru-cache.cpp	O(1) for { get(key), put(key, value) }	O(n)
153	Medium	Find Minimum in Rotated Sorted Array	153-find-minimum-in-rotated-sorted-array.cpp	O(log(n))	O(log(n))
155	Medium	Min Stack	155-min-stack.cpp	O(1) for { push(x), pop(), top(), getMin() }	O(n)
165	Medium	Compare Version Numbers	165-compare-version-numbers.cpp	O(n1+n2)	O(1)
167	Medium	Two Sum II - Input Array Is Sorted	167-two-sum-ii-input-array-is-sorted.cpp	O(n)	O(1)
174	Hard	Dungeon Game	174-dungeon-game.cpp	O(m*n)	O(m*n)
189	Medium	Rotate Array	189-rotate-array.cpp	O(n)	O(1)
190	Easy	Reverse Bits	190-reverse-bits.cpp	O(1)	O(1)
191	Easy	Number of 1 Bits	191-number-of-1-bits.cpp	O(1)	O(1)
198	Medium	House Robber	198-house-robber.cpp	O(n)	O(n)
200	Medium	Number of Islands	200-number-of-islands.cpp	O(m*n)	O(m*n)
201	Medium	Bitwise AND of Numbers Range	201-bitwise-and-of-numbers-range.cpp	O(log(n))	O(1)
202	Easy	Happy Number	202-happy-number.cpp	O(n)	O(1)
205	Easy	Isomorphic Strings	205-isomorphic-strings.cpp	O(n)	O(1)
206	Easy	Reverse Linked List	206-reverse-linked-list.cpp	O(n)	O(1)
208	Medium	Implement Trie (Prefix Tree)	208-implement-trie-prefix-tree.cpp	O(n) for { insert(word), search(word), startsWith(prefix) }	O(n)
213	Medium	House Robber II	213-house-robber-ii.cpp	O(n)	O(n)
215	Medium	Kth Largest Element in an Array	215-kth-largest-element-in-an-array.cpp	O(n*log(k))	O(k)
217	Easy	Contains Duplicate	217-contains-duplicate.cpp	O(n)	O(n)
218	Hard	The Skyline Problem	218-the-skyline-problem.cpp	O(n*log(n))	O(n)
221	Medium	Maximal Square	221-maximal-square.cpp	O(m*n)	O(m*n)
231	Easy	Power of Two	231-power-of-two.cpp	O(1)	O(1)
234	Easy	Palindrome Linked List	234-palindrome-linked-list.cpp	O(n)	O(n)
235	Medium	Lowest Common Ancestor of a Binary Search Tree	235-lowest-common-ancestor-of-a-binary-search-tree.cpp	O(h)	O(h) or O(1) with tail-call optimization
238	Medium	Product of Array Except Self	238-product-of-array-except-self.cpp	O(n)	O(n)
268	Easy	Missing Number	268-missing-number.cpp	O(n)	O(1)
278	Easy	First Bad Version	278-first-bad-version.cpp	O(log(n))	O(1)
283	Easy	Move Zeroes	283-move-zeroes.cpp	O(n)	O(1)
299	Medium	Bulls and Cows	299-bulls-and-cows.cpp	O(n)	O(1)
300	Medium	Longest Increasing Subsequence	300-longest-increasing-subsequence.cpp	O(n*log(n))	O(n)
322	Medium	Coin Change	322-coin-change.cpp	O(K*M)	O(K*M)
326	Easy	Power of Three	326-power-of-three.cpp	O(1)	O(1)
342	Easy	Power of Four	342-power-of-four.cpp	O(1)	O(1)
344	Easy	Reverse String	344-reverse-string.cpp	O(n)	O(1)
347	Medium	Top K Frequent Elements	347-top-k-frequent-elements.cpp	O(n)	O(n)
349	Easy	Intersection of Two Arrays	349-intersection-of-two-arrays.cpp	O(n1+n2)	O(n1+n2)
350	Easy	Intersection of Two Arrays II	350-intersection-of-two-arrays-ii.cpp	O(n1+n2)	O(n1+n2)
373	Medium	Find K Pairs with Smallest Sums	373-find-k-pairs-with-smallest-sums.cpp	O(k*log(k))	O(k)
383	Easy	Ransom Note	383-ransom-note.cpp	O(m+n)	O(1)
387	Easy	First Unique Character in a String	387-first-unique-character-in-a-string.cpp	O(n)	O(1)
392	Easy	Is Subsequence	392-is-subsequence.cpp	O(m+n)	O(1)
394	Medium	Decode String	394-decode-string.cpp	O(n)	O(n)
409	Easy	Longest Palindrome	409-longest-palindrome.cpp	O(n)	O(1)
438	Medium	Find All Anagrams in a String	438-find-all-anagrams-in-a-string.cpp	O(m+n)	O(m)
496	Easy	Next Greater Element I	496-next-greater-element-i.cpp	O(n1+n2)	O(n1+n2)
503	Medium	Next Greater Element II	503-next-greater-element-ii.cpp	O(n)	O(n)
509	Easy	Fibonacci Number	509-fibonacci-number.cpp	O(log(n))	O(log(n))
525	Medium	Contiguous Array	525-contiguous-array.cpp	O(n)	O(n)
542	Medium	01 Matrix	542-01-matrix.cpp	O(m*n)	O(m*n)
543	Easy	Diameter of Binary Tree	543-diameter-of-binary-tree.cpp	O(n)	O(n)
557	Easy	Reverse Words in a String III	557-reverse-words-in-a-string-iii.cpp	O(n)	O(1)
560	Medium	Subarray Sum Equals K	560-subarray-sum-equals-k.cpp	O(n)	O(n)
565	Medium	Array Nesting	565-array-nesting.cpp	O(n)	O(n)
566	Easy	Reshape the Matrix	566-reshape-the-matrix.cpp	O(m*n)	O(m*n)
567	Medium	Permutation in String	567-permutation-in-string.cpp	O(n1+n2)	O(1)
587	Hard	Erect the Fence	587-erect-the-fence.cpp	O(n*log(n))	O(n)
589	Easy	N-ary Tree Preorder Traversal	589-n-ary-tree-preorder-traversal.cpp	O(n)	O(n)
617	Easy	Merge Two Binary Trees	617-merge-two-binary-trees.cpp	O(n1+n2)	O(n1+n2)
647	Medium	Palindromic Substrings	647-palindromic-substrings.cpp	O(n^2)	O(1)
678	Medium	Valid Parenthesis String	678-valid-parenthesis-string.cpp	O(n)	O(1)
692	Medium	Top K Frequent Words	692-top-k-frequent-words.cpp	O(n*log(k))	O(n)
695	Medium	Max Area of Island	695-max-area-of-island.cpp	O(m*n)	O(m*n)
704	Easy	Binary Search	704-binary-search.cpp	O(log(n))	O(1)
724	Easy	Find Pivot Index	724-find-pivot-index.cpp	O(n)	O(1)
733	Easy	Flood Fill	733-flood-fill.cpp	O(m*n)	O(m*n)
739	Medium	Daily Temperatures	739-daily-temperatures.cpp	O(n)	O(n)
746	Easy	Min Cost Climbing Stairs	746-min-cost-climbing-stairs.cpp	O(n)	O(n)
764	Medium	Largest Plus Sign	764-largest-plus-sign.cpp	O(n^2)	O(n^2)
784	Medium	Letter Case Permutation	784-letter-case-permutation.cpp	O(n*2^n)	O(n*2^n)
844	Easy	Backspace String Compare	844-backspace-string-compare.cpp	O(n)	O(1)
848	Medium	Shifting Letters	848-shifting-letters.cpp	O(n)	O(n)
865	Medium	Smallest Subtree with all the Deepest Nodes	865-smallest-subtree-with-all-the-deepest-nodes.cpp	O(n)	O(n)
876	Easy	Middle of the Linked List	876-middle-of-the-linked-list.cpp	O(n)	O(1)
899	Hard	Orderly Queue	899-orderly-queue.cpp	O(n^2)	O(n)
917	Easy	Reverse Only Letters	917-reverse-only-letters.cpp	O(n)	O(n)
929	Easy	Unique Email Addresses	929-unique-email-addresses.cpp	O(n)	O(n)
977	Easy	Squares of a Sorted Array	977-squares-of-a-sorted-array.cpp	O(n)	O(n)
978	Medium	Longest Turbulent Subarray	978-longest-turbulent-subarray.cpp	O(n)	O(1)
994	Medium	Rotting Oranges	994-rotting-oranges.cpp	O(m*n)	O(m*n)
1008	Medium	Construct Binary Search Tree from Preorder Traversal	1008-construct-binary-search-tree-from-preorder-traversal.cpp	O(n*log(n)) maybe?	O(n)
1011	Medium	Capacity To Ship Packages Within D Days	1011-capacity-to-ship-packages-within-d-days.cpp	O(n*log(sum(W)-max(W))), where W = the weights of packages	O(1)
1046	Easy	Last Stone Weight	1046-last-stone-weight.cpp	O(n*log(n))	O(n)
1137	Easy	N-th Tribonacci Number	1137-n-th-tribonacci-number.cpp	O(n)	O(n)
1143	Medium	Longest Common Subsequence	1143-longest-common-subsequence.cpp	O(n1*n2)	O(n1*n2)
1189	Easy	Maximum Number of Balloons	1189-maximum-number-of-balloons.cpp	O(n)	O(1)
1426	Easy	Counting Elements	1426-counting-elements.cpp	O(n)	O(n)
1427	Easy	Perform String Shifts	1427-perform-string-shifts.cpp	O(m+n)	O(n)
1428	Medium	Leftmost Column with at Least a One	1428-leftmost-column-with-at-least-a-one.cpp	O(r+c)	O(1)
1429	Medium	First Unique Number	1429-first-unique-number.cpp	O(1) for { showFirstUnique(), add(value) }	O(n)
1430	Medium	Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree	1430-check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree.cpp	O(n)	O(n)
1475	Easy	Final Prices With a Special Discount in a Shop	1475-final-prices-with-a-special-discount-in-a-shop.cpp	O(n)	O(n)
1480	Easy	Running Sum of 1d Array	1480-running-sum-of-1d-array.cpp	O(n)	O(n)
1629	Easy	Slowest Key	1629-slowest-key.cpp	O(n)	O(1)
1944	Hard	Number of Visible People in a Queue	1944-number-of-visible-people-in-a-queue.cpp	O(n)	O(n)
1985	Medium	Find the Kth Largest Integer in the Array	1985-find-the-kth-largest-integer-in-the-array.cpp	O(n), on average	O(1)
2487	Medium	Remove Nodes From Linked List	2487-remove-nodes-from-linked-list.cpp	O(n)	O(1)

SQL

No.	Difficulty	Title	Code	Time complexity	Space complexity
175	Easy	Combine Two Tables	175-combine-two-tables.sql	N/A	N/A
176	Medium	Second Highest Salary	176-second-highest-salary.sql	N/A	N/A
182	Easy	Duplicate Emails	182-duplicate-emails.sql	N/A	N/A
183	Easy	Customers Who Never Order	183-customers-who-never-order.sql	N/A	N/A
196	Easy	Delete Duplicate Emails	196-delete-duplicate-emails.sql	N/A	N/A
197	Easy	Rising Temperature	197-rising-temperature.sql	N/A	N/A
511	Easy	Game Play Analysis I	511-game-play-analysis-i.sql	N/A	N/A
570	Medium	Managers with at Least 5 Direct Reports	570-managers-with-at-least-5-direct-reports.sql	N/A	N/A
577	Easy	Employee Bonus	577-employee-bonus.sql	N/A	N/A
584	Easy	Find Customer Referee	584-find-customer-referee.sql	N/A	N/A
586	Easy	Customer Placing the Largest Number of Orders	586-customer-placing-the-largest-number-of-orders.sql	N/A	N/A
595	Easy	Big Countries	595-big-countries.sql	N/A	N/A
607	Easy	Sales Person	607-sales-person.sql	N/A	N/A
608	Medium	Tree Node	608-tree-node.sql	N/A	N/A
620	Easy	Not Boring Movies	620-not-boring-movies.sql	N/A	N/A
627	Easy	Swap Salary	627-swap-salary.sql	N/A	N/A
1050	Easy	Actors and Directors Who Cooperated At Least Three Times	1050-actors-and-directors-who-cooperated-at-least-three-times.sql	N/A	N/A
1068	Easy	Product Sales Analysis I	1068-product-sales-analysis-i.sql	N/A	N/A
1084	Easy	Sales Analysis III	1084-sales-analysis-iii.sql	N/A	N/A
1141	Easy	User Activity for the Past 30 Days I	1141-user-activity-for-the-past-30-days-i.sql	N/A	N/A
1148	Easy	Article Views I	1148-article-views-i.sql	N/A	N/A
1158	Medium	Market Analysis I	1158-market-analysis-i.sql	N/A	N/A
1280	Easy	Students and Examinations	1280-students-and-examinations.sql	N/A	N/A
1378	Easy	Replace Employee ID With The Unique Identifier	1378-replace-employee-id-with-the-unique-identifier.sql	N/A	N/A
1393	Medium	Capital Gain/Loss	1393-capital-gainloss.sql	N/A	N/A
1407	Easy	Top Travellers	1407-top-travellers.sql	N/A	N/A
1484	Easy	Group Sold Products By The Date	1484-group-sold-products-by-the-date.sql	N/A	N/A
1527	Easy	Patients With a Condition	1527-patients-with-a-condition.sql	N/A	N/A
1581	Easy	Customer Who Visited but Did Not Make Any Transactions	1581-customer-who-visited-but-did-not-make-any-transactions.sql	N/A	N/A
1587	Easy	Bank Account Summary II	1587-bank-account-summary-ii.sql	N/A	N/A
1661	Easy	Average Time of Process per Machine	1661-average-time-of-process-per-machine.sql	N/A	N/A
1667	Easy	Fix Names in a Table	1667-fix-names-in-a-table.sql	N/A	N/A
1683	Easy	Invalid Tweets	1683-invalid-tweets.sql	N/A	N/A
1693	Easy	Daily Leads and Partners	1693-daily-leads-and-partners.sql	N/A	N/A
1729	Easy	Find Followers Count	1729-find-followers-count.sql	N/A	N/A
1741	Easy	Find Total Time Spent by Each Employee	1741-find-total-time-spent-by-each-employee.sql	N/A	N/A
1757	Easy	Recyclable and Low Fat Products	1757-recyclable-and-low-fat-products.sql	N/A	N/A
1795	Easy	Rearrange Products Table	1795-rearrange-products-table.sql	N/A	N/A
1873	Easy	Calculate Special Bonus	1873-calculate-special-bonus.sql	N/A	N/A
1890	Easy	The Latest Login in 2020	1890-the-latest-login-in-2020.sql	N/A	N/A
1934	Medium	Confirmation Rate	1934-confirmation-rate.sql	N/A	N/A
1965	Easy	Employees With Missing Information	1965-employees-with-missing-information.sql	N/A	N/A

TypeScript

No.	Difficulty	Title	Code	Time complexity	Space complexity
2619	Easy	Array Prototype Last	2619-array-prototype-last.ts	N/A	N/A
2620	Easy	Counter	2620-counter.ts	N/A	N/A
2621	Easy	Sleep	2621-sleep.ts	N/A	N/A
2622	Medium	Cache With Time Limit	2622-cache-with-time-limit.ts	N/A	N/A
2623	Medium	Memoize	2623-memoize.ts	N/A	N/A
2625	Medium	Flatten Deeply Nested Array	2625-flatten-deeply-nested-array.ts	N/A	N/A
2626	Easy	Array Reduce Transformation	2626-array-reduce-transformation.ts	N/A	N/A
2627	Medium	Debounce	2627-debounce.ts	N/A	N/A
2629	Easy	Function Composition	2629-function-composition.ts	N/A	N/A
2631	Medium	Group By	2631-group-by.ts	N/A	N/A
2634	Easy	Filter Elements from Array	2634-filter-elements-from-array.ts	N/A	N/A
2635	Easy	Apply Transform Over Each Element in Array	2635-apply-transform-over-each-element-in-array.ts	N/A	N/A
2637	Medium	Promise Time Limit	2637-promise-time-limit.ts	N/A	N/A
2665	Easy	Counter II	2665-counter-ii.ts	N/A	N/A
2666	Easy	Allow One Function Call	2666-allow-one-function-call.ts	N/A	N/A
2667	Easy	Create Hello World Function	2667-create-hello-world-function.ts	N/A	N/A
2677	Easy	Chunk Array	2677-chunk-array.ts	N/A	N/A
2694	Medium	Event Emitter	2694-event-emitter.ts	N/A	N/A
2695	Easy	Array Wrapper	2695-array-wrapper.ts	N/A	N/A
2703	Easy	Return Length of Arguments Passed	2703-return-length-of-arguments-passed.ts	N/A	N/A
2704	Easy	To Be Or Not To Be	2704-to-be-or-not-to-be.ts	N/A	N/A
2705	Medium	Compact Object	2705-compact-object.ts	N/A	N/A
2715	Easy	Execute Cancellable Function With Delay	2715-execute-cancellable-function-with-delay.ts	N/A	N/A
2721	Medium	Execute Asynchronous Functions in Parallel	2721-execute-asynchronous-functions-in-parallel.ts	N/A	N/A
2722	Medium	Join Two Arrays by ID	2722-join-two-arrays-by-id.ts	N/A	N/A
2723	Easy	Add Two Promises	2723-add-two-promises.ts	N/A	N/A
2724	Easy	Sort By	2724-sort-by.ts	N/A	N/A
2725	Easy	Interval Cancellation	2725-interval-cancellation.ts	N/A	N/A
2726	Easy	Calculator with Method Chaining	2726-calculator-with-method-chaining.ts	N/A	N/A
2727	Easy	Is Object Empty	2727-is-object-empty.ts	N/A	N/A