LeetCode Submissions

My accepted LeetCode solutions, synced automatically from my submission history. Problems are grouped by their primary topic tag.

235 problems solved  ·  69 Easy  ·  133 Medium  ·  33 Hard

Languages: C++, Java

Last synced 2026-08-31 by _sync (how it works).

Array (1)

#	Problem	Difficulty	Solutions
674	Longest Continuous Increasing Subsequence	Easy	Java

Backtracking (12)

#	Problem	Difficulty	Solutions
17	Letter Combinations of a Phone Number	Medium	Java
39	Combination Sum	Medium	Java
40	Combination Sum II	Medium	Java
46	Permutations	Medium	Java
51	N-Queens	Hard	Java
77	Combinations	Medium	C++ Java
78	Subsets	Medium	Java
79	Word Search	Medium	Java
90	Subsets II	Medium	Java
257	Binary Tree Paths	Easy	Java
980	Unique Paths III	Hard	Java
1863	Sum of All Subset XOR Totals	Easy	Java

Binary Search (10)

#	Problem	Difficulty	Solutions
4	Median of Two Sorted Arrays	Hard	Java
33	Search in Rotated Sorted Array	Medium	Java
35	Search Insert Position	Easy	Java
69	Sqrt(x)	Easy	Java
74	Search a 2D Matrix	Medium	Java
153	Find Minimum in Rotated Sorted Array	Medium	Java
209	Minimum Size Subarray Sum	Medium	Java
268	Missing Number	Easy	Java
704	Binary Search	Easy	Java
875	Koko Eating Bananas	Medium	Java

Bit Manipulation (9)

#	Problem	Difficulty	Solutions
67	Add Binary	Easy	Java
136	Single Number	Easy	Java
201	Bitwise AND of Numbers Range	Medium	Java
371	Sum of Two Integers	Medium	Java
982	Triples with Bitwise AND Equal To Zero	Hard	Java
1342	Number of Steps to Reduce a Number to Zero	Easy	C++ Java
1486	XOR Operation in an Array	Easy	C++
1720	Decode XORed Array	Easy	Java
3702	Longest Subsequence With Non-Zero Bitwise XOR	Medium	Java

Breadth-First Search (4)

#	Problem	Difficulty	Solutions
127	Word Ladder	Hard	Java
994	Rotting Oranges	Medium	Java
1091	Shortest Path in Binary Matrix	Medium	Java
1293	Shortest Path in a Grid with Obstacles Elimination	Hard	Java

Bucket Sort (2)

#	Problem	Difficulty	Solutions
347	Top K Frequent Elements	Medium	Java
451	Sort Characters By Frequency	Medium	Java

Data Stream (3)

#	Problem	Difficulty	Solutions
295	Find Median from Data Stream	Hard	Java
703	Kth Largest Element in a Stream	Easy	Java
933	Number of Recent Calls	Easy	Java

Depth-First Search (2)

#	Problem	Difficulty	Solutions
417	Pacific Atlantic Water Flow	Medium	Java
733	Flood Fill	Easy	Java

Design (6)

#	Problem	Difficulty	Solutions
304	Range Sum Query 2D - Immutable	Medium	Java
900	RLE Iterator	Medium	Java
981	Time Based Key-Value Store	Medium	C++ Java
1146	Snapshot Array	Medium	Java
1603	Design Parking System	Easy	Java
1865	Finding Pairs With a Certain Sum	Medium	Java

Divide and Conquer (2)

#	Problem	Difficulty	Solutions
190	Reverse Bits	Easy	Java
191	Number of 1 Bits	Easy	Java

Doubly-Linked List (3)

#	Problem	Difficulty	Solutions
146	LRU Cache	Medium	Java
432	All O`one Data Structure	Hard	C++
460	LFU Cache	Hard	Java

Dynamic Programming (31)

#	Problem	Difficulty	Solutions
5	Longest Palindromic Substring	Medium	Java
22	Generate Parentheses	Medium	Java
45	Jump Game II	Medium	Java
53	Maximum Subarray	Medium	C++ Java
55	Jump Game	Medium	Java
63	Unique Paths II	Medium	Java
64	Minimum Path Sum	Medium	Java
70	Climbing Stairs	Easy	Java
91	Decode Ways	Medium	Java
121	Best Time to Buy and Sell Stock	Easy	C++ Java
122	Best Time to Buy and Sell Stock II	Medium	C++
124	Binary Tree Maximum Path Sum	Hard	Java
131	Palindrome Partitioning	Medium	Java
198	House Robber	Medium	Java
213	House Robber II	Medium	Java
241	Different Ways to Add Parentheses	Medium	Java
264	Ugly Number II	Medium	Java
279	Perfect Squares	Medium	Java
329	Longest Increasing Path in a Matrix	Hard	Java
338	Counting Bits	Easy	Java
343	Integer Break	Medium	Java
392	Is Subsequence	Easy	Java
410	Split Array Largest Sum	Hard	Java
473	Matchsticks to Square	Medium	Java
509	Fibonacci Number	Easy	Java
647	Palindromic Substrings	Medium	Java
746	Min Cost Climbing Stairs	Easy	Java
845	Longest Mountain in Array	Medium	Java
978	Longest Turbulent Subarray	Medium	Java
1137	N-th Tribonacci Number	Easy	Java
1928	Minimum Cost to Reach Destination in Time	Hard	Java

Game Theory (4)

#	Problem	Difficulty	Solutions
877	Stone Game	Medium	Java
1563	Stone Game V	Hard	Java
1927	Sum Game	Medium	Java
2029	Stone Game IX	Medium	Java

Graph Theory (7)

#	Problem	Difficulty	Solutions
133	Clone Graph	Medium	Java
207	Course Schedule	Medium	Java
210	Course Schedule II	Medium	Java
310	Minimum Height Trees	Medium	Java
332	Reconstruct Itinerary	Hard	Java
802	Find Eventual Safe States	Medium	Java
2392	Build a Matrix With Conditions	Hard	Java

Greedy (9)

#	Problem	Difficulty	Solutions
134	Gas Station	Medium	Java
649	Dota2 Senate	Medium	Java
846	Hand of Straights	Medium	Java
860	Lemonade Change	Easy	Java
1386	Cinema Seat Allocation	Medium	Java
1689	Partitioning Into Minimum Number Of Deci-Binary Numbers	Medium	Java
2091	Removing Minimum and Maximum From Array	Medium	Java
2131	Longest Palindrome by Concatenating Two Letter Words	Medium	Java
3720	Lexicographically Smallest Permutation Greater Than Target	Medium	Java

Hash Table (5)

#	Problem	Difficulty	Solutions
1	Two Sum	Easy	Java
205	Isomorphic Strings	Easy	Java
929	Unique Email Addresses	Easy	Java
3471	Find the Largest Almost Missing Integer	Easy	C++
3718	Smallest Missing Multiple of K	Easy	Java

Heap (Priority Queue) (7)

#	Problem	Difficulty	Solutions
373	Find K Pairs with Smallest Sums	Medium	Java
378	Kth Smallest Element in a Sorted Matrix	Medium	Java
621	Task Scheduler	Medium	Java
1046	Last Stone Weight	Easy	Java
1094	Car Pooling	Medium	Java
1405	Longest Happy String	Medium	Java
2402	Meeting Rooms III	Hard	Java

Interactive (2)

#	Problem	Difficulty	Solutions
278	First Bad Version	Easy	Java
374	Guess Number Higher or Lower	Easy	Java

Linked List (14)

#	Problem	Difficulty	Solutions
2	Add Two Numbers	Medium	Java
19	Remove Nth Node From End of List	Medium	Java
21	Merge Two Sorted Lists	Easy	Java
23	Merge k Sorted Lists	Hard	Java
25	Reverse Nodes in k-Group	Hard	Java
83	Remove Duplicates from Sorted List	Easy	Java
138	Copy List with Random Pointer	Medium	Java
141	Linked List Cycle	Easy	Java
143	Reorder List	Medium	Java
206	Reverse Linked List	Easy	Java
237	Delete Node in a Linked List	Medium	Java
355	Design Twitter	Medium	Java
876	Middle of the Linked List	Easy	Java
2807	Insert Greatest Common Divisors in Linked List	Medium	Java

Math (4)

#	Problem	Difficulty	Solutions
7	Reverse Integer	Medium	Java
66	Plus One	Easy	Java
168	Excel Sheet Column Title	Easy	Java
3622	Check Divisibility by Digit Sum and Product	Easy	Java

Matrix (3)

#	Problem	Difficulty	Solutions
36	Valid Sudoku	Medium	Java
48	Rotate Image	Medium	Java
54	Spiral Matrix	Medium	Java

Monotonic Queue (2)

#	Problem	Difficulty	Solutions
239	Sliding Window Maximum	Hard	Java
918	Maximum Sum Circular Subarray	Medium	Java

Monotonic Stack (5)

#	Problem	Difficulty	Solutions
42	Trapping Rain Water	Hard	Java
84	Largest Rectangle in Histogram	Hard	Java
739	Daily Temperatures	Medium	Java
853	Car Fleet	Medium	Java
901	Online Stock Span	Medium	Java

Ordered Set (2)

#	Problem	Difficulty	Solutions
895	Maximum Frequency Stack	Hard	Java
2251	Number of Flowers in Full Bloom	Hard	Java

Prefix Sum (4)

#	Problem	Difficulty	Solutions
238	Product of Array Except Self	Medium	Java
560	Subarray Sum Equals K	Medium	Java
724	Find Pivot Index	Easy	Java
1480	Running Sum of 1d Array	Easy	Java

Quickselect (2)

#	Problem	Difficulty	Solutions
215	Kth Largest Element in an Array	Medium	Java
973	K Closest Points to Origin	Medium	Java

Segment Tree (2)

#	Problem	Difficulty	Solutions
2213	Longest Substring of One Repeating Character	Hard	Java
2276	Count Integers in Intervals	Hard	Java

Shortest Path (3)

#	Problem	Difficulty	Solutions
743	Network Delay Time	Medium	Java
787	Cheapest Flights Within K Stops	Medium	Java
1334	Find the City With the Smallest Number of Neighbors at a Threshold Distance	Medium	Java

Simulation (2)

#	Problem	Difficulty	Solutions
68	Text Justification	Hard	Java
3069	Distribute Elements Into Two Arrays I	Easy	C++

Sliding Window (5)

#	Problem	Difficulty	Solutions
3	Longest Substring Without Repeating Characters	Medium	Java
76	Minimum Window Substring	Hard	Java
424	Longest Repeating Character Replacement	Medium	Java
438	Find All Anagrams in a String	Medium	C++
3090	Maximum Length Substring With Two Occurrences	Easy	Java

Sorting (5)

#	Problem	Difficulty	Solutions
49	Group Anagrams	Medium	Java
56	Merge Intervals	Medium	Java
217	Contains Duplicate	Easy	Java
229	Majority Element II	Medium	Java
242	Valid Anagram	Easy	Java

Stack (8)

#	Problem	Difficulty	Solutions
20	Valid Parentheses	Easy	Java
94	Binary Tree Inorder Traversal	Easy	Java
144	Binary Tree Preorder Traversal	Easy	Java
145	Binary Tree Postorder Traversal	Easy	Java
150	Evaluate Reverse Polish Notation	Medium	Java
155	Min Stack	Medium	Java
394	Decode String	Medium	Java
735	Asteroid Collision	Medium	Java

String (2)

#	Problem	Difficulty	Solutions
8	String to Integer (atoi)	Medium	Java
2468	Split Message Based on Limit	Hard	Java

Tree (20)

#	Problem	Difficulty	Solutions
98	Validate Binary Search Tree	Medium	Java
100	Same Tree	Easy	Java
102	Binary Tree Level Order Traversal	Medium	Java
104	Maximum Depth of Binary Tree	Easy	Java
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	Java
110	Balanced Binary Tree	Easy	Java
112	Path Sum	Easy	C++
199	Binary Tree Right Side View	Medium	Java
222	Count Complete Tree Nodes	Medium	Java
226	Invert Binary Tree	Easy	Java
230	Kth Smallest Element in a BST	Medium	Java
235	Lowest Common Ancestor of a Binary Search Tree	Medium	Java
297	Serialize and Deserialize Binary Tree	Hard	Java
427	Construct Quad Tree	Medium	Java
450	Delete Node in a BST	Medium	Java
543	Diameter of Binary Tree	Easy	Java
572	Subtree of Another Tree	Easy	Java
1448	Count Good Nodes in Binary Tree	Medium	Java
2096	Step-By-Step Directions From a Binary Tree Node to Another	Medium	C++
2246	Longest Path With Different Adjacent Characters	Hard	C++

Trie (5)

#	Problem	Difficulty	Solutions
14	Longest Common Prefix	Easy	Java
208	Implement Trie (Prefix Tree)	Medium	Java
211	Design Add and Search Words Data Structure	Medium	Java
212	Word Search II	Hard	Java
3043	Find the Length of the Longest Common Prefix	Medium	Java

Two Pointers (17)

#	Problem	Difficulty	Solutions
11	Container With Most Water	Medium	Java
15	3Sum	Medium	C++ Java
16	3Sum Closest	Medium	Java
27	Remove Element	Easy	Java
125	Valid Palindrome	Easy	Java
167	Two Sum II - Input Array Is Sorted	Medium	Java
189	Rotate Array	Medium	Java
202	Happy Number	Easy	Java
283	Move Zeroes	Easy	Java
287	Find the Duplicate Number	Medium	Java
344	Reverse String	Easy	Java
557	Reverse Words in a String III	Easy	Java
567	Permutation in String	Medium	C++ Java
680	Valid Palindrome II	Easy	Java
881	Boats to Save People	Medium	Java
977	Squares of a Sorted Array	Easy	Java
1768	Merge Strings Alternately	Easy	Java

Union-Find (11)

#	Problem	Difficulty	Solutions
128	Longest Consecutive Sequence	Medium	Java
130	Surrounded Regions	Medium	Java
200	Number of Islands	Medium	Java
399	Evaluate Division	Medium	Java
547	Number of Provinces	Medium	Java
684	Redundant Connection	Medium	Java
695	Max Area of Island	Medium	Java
778	Swim in Rising Water	Hard	Java
1584	Min Cost to Connect All Points	Medium	Java
1631	Path With Minimum Effort	Medium	Java
2948	Make Lexicographically Smallest Array by Swapping Elements	Medium	Java