LeetCode Problems

I like solving problems with code, and LeetCode has thousands to choose from! You can also see my full LeetCode profile.

000-499

#	Problem	Difficulty	Language	Topics
0001	Two Sum	Easy	JavaScript, TypeScript	array hash table
0006	ZigZag Conversion	Medium	TypeScript	string
0009	Palindrome Number	Easy	JavaScript	math
0011	Container With Most Water	Medium	TypeScript	array two pointers greedy
0014	Longest Common Prefix	Easy	JavaScript	string trie
0020	Valid Parentheses	Easy	TypeScript	string stack
0026	Remove Duplicates from Sorted Array	Easy	TypeScript	array two pointers
0027	Remove Element	Easy	TypeScript	array two pointers
0028	Find the Index of the First Occurrence in a String	Easy	TypeScript	two pointers string string matching
0049	Group Anagrams	Medium	TypeScript	array hash table string sorting
0058	Length of Last Word	Easy	TypeScript	string
0066	Plus One	Easy	TypeScript	array math
0068	Text Justification	Hard	TypeScript	array string simulation
0074	Search a 2D Matrix	Medium	JavaScript	array binary search matrix
0075	Sort Colors	Medium	TypeScript	array two pointers sorting
0101	Symmetric Tree	Easy	TypeScript	tree depth-first search breadth-first search binary tree
0121	Best Time to Buy and Sell Stock	Easy	JavaScript	array dynamic programming
0125	Valid Palindrome	Easy	JavaScript	two pointers string
0130	Surrounded Regions	Medium	TypeScript	array depth-first search breadth-first search union find matrix
0131	Palindrome Partitioning	Medium	TypeScript	string dynamic programming backtracking
0136	Single Number	Easy	TypeScript	array bit manipulation
0151	Reverse Words in a String	Medium	TypeScript	two pointers string
0169	Majority Element	Easy	JavaScript	array hash table divide and conquer sorting counting
0175	Combine Two Tables	Easy	T-SQL	database
0176	Second Highest Salary	Medium	T-SQL	database
0181	Employees Earning More than their Managers	Easy	T-SQL	database
0202	Happy Number	Easy	TypeScript	hash table math two pointers
0205	Isomorphic Strings	Easy	TypeScript	hash table string
0217	Contains Duplicate	Easy	JavaScript, TypeScript	array hash table sorting
0238	Product of Array Except Self	Medium	TypeScript	array prefix sum
0242	Valid Anagram	Easy	TypeScript	array prefix sum
0260	Single Number III	Medium	TypeScript	array bit manipulation
0283	Move Zeroes	Easy	TypeScript	hash table string sorting
0330	Patching Array	Medium	TypeScript	array greedy
0334	Increasing Triplet Subsequence	Medium	TypeScript	array greedy
0344	Reverse String	Easy	TypeScript	string two pointers
0345	Reverse Vowels of a String	Easy	TypeScript	string two pointers
0350	Intersection of Two Arrays	Easy	TypeScript	array hash table two pointers binary search sorting
0383	Ransom Note	Easy	TypeScript	hash table string counting
0392	Is Subsequence	Easy	TypeScript	two pointers string dynamic programming
0409	Longest Palindrome	Easy	TypeScript	hash table string greedy
0448	Find all Numbers Disappeared in an Array	Easy	JavaScript	array hash table
0463	Island Perimeter	Easy	TypeScript	array depth-first search breadth-first search matrix
0482	License Key Formatting	Easy	TypeScript	string

500-999

#	Problem	Difficulty	Language	Topics
0502	IPO	Medium	TypeScript	array greedy sorting heap (priority queue)
0523	Continuous Subarray Sum	Hard	TypeScript	array hash table math prefix sum
0605	Can Place Flowers	Easy	TypeScript	array greedy
0605	Can Place Flowers	Easy	TypeScript	array greedy
0633	Sum of Square Numbers	Medium	TypeScript	math two pointers binary search
0643	Maximum Average Subarray I	Easy	TypeScript	array sliding window
0648	Replace Words	Medium	TypeScript	array hash table string trie
0657	Robot Return to Origin	Easy	TypeScript	string simulation
0724	Find Pivot Index	Easy	TypeScript	array prefix sum
0726	Number of Atoms	Hard	TypeScript	hash table string stack sorting
0748	Shortest Completing Word	Easy	TypeScript	array hash table string
0796	Rotate String	Easy	TypeScript	string string matching
0819	Most Common Word	Easy	TypeScript	array hash table string counting
0826	Most Profit Assigning Work	Medium	TypeScript	array two pointers binary search greedy sorting
0846	Hand of Straights	Medium	TypeScript	array hash table greedy sorting
0945	Minimum Increment to Make Array Unique	Medium	TypeScript	array greedy sorting counting
0973	K Closest Points to Origin	Medium	TypeScript	array math divide and conquer geometry sorting heap (priority queue) quickselect
0974	Subarray Sums Divisible by K	Medium	TypeScript	array bit manipulation queue sliding window prefix sum
0995	Minimum Number of K Consecutive Bit Flips	Hard	TypeScript	array hash table graph
0997	Find the Town Judge	Easy	TypeScript	array hash table graph

1000-1499

#	Problem	Difficulty	Language	Topics
1002	Find Common Characters	Easy	TypeScript	array hash table string
1004	Max Consecutive Ones III	Medium	TypeScript	array binary search sliding window prefix sum
1013	Partition Array Into Three Parts With Equal Sum	Easy	TypeScript	array greedy
1038	Binary Search Tree to Greater Sum Tree	Medium	TypeScript	tree depth-first search binary search tree binary tree
1051	Height Checker	Easy	TypeScript	array sorting counting list
1052	Grumpy Bookstore Owner	Medium	TypeScript	array sliding window
1071	Greatest Common Divisor of Strings	Easy	TypeScript	math string
1108	Defanging an IP Address	Easy	TypeScript	string
1110	Delete Nodes and Return Forest	Medium	TypeScript	array hash table tree depth-first search binary tree
1122	Relative Sort Array	Easy	TypeScript	array hash table sorting counting sort
1190	Reverse Substrings Between Each Pair of Parentheses	Medium	TypeScript	string stack
1207	Unique Number of Occurrences	Easy	TypeScript	array hash table
1208	Get Equal Substrings Within Budget	Medium	TypeScript	string binary search sliding window prefix sum
1248	Count Number of Nice Subarrays	Medium	TypeScript	array hash table math sliding window
1281	Subtract the Product and Sum of Digits of an Integer	Easy	TypeScript	math
1380	Lucky Numbers in a Matrix	Easy	TypeScript	array matrix
1382	Balance a Binary Search Tree	Medium	TypeScript	divide and conquer greedy tree depth-first search binary search tree binary tree
1404	Number of Steps to Reduce a Number in Binary Representation to One	Medium	TypeScript	string bit manipulation
1431	Kid With the Greatest Number of Candies	Easy	TypeScript	array
1438	Longest Continuous Subarray with Absolute Diff Less than or Equal to Limit	Medium	TypeScript	array queue sliding window heap (priority queue) ordered set monotonic queue
1442	Count Triplets That Can Form Two Arrays of Equal XOR	Medium	TypeScript	array hash table math bit manipulation prefix sum
1456	Maximum Number of Vowels in a Substring of Given Length	Medium	TypeScript	string sliding window
1482	Minimum Number of Days to Make m Bouquets	Medium	TypeScript	array binary search

1500-1999

#	Problem	Difficulty	Language	Topics
1509	Minimum Difference Between Largest and Smallest Value in Three Moves	Medium	TypeScript	array greedy sorting
1518	Water Bottles	Easy	TypeScript	math simulation
1530	Number of Good Leaf Nodes Pairs	Medium	TypeScript	tree depth-first search binary tree
1550	Three Consecutive Odds	Easy	TypeScript	array
1552	Magnetic Force Between Two Balls	Medium	TypeScript	array binary search sorting
1579	Remove Max Number of Edges to Keep Graph Fully Traversable	Hard	TypeScript	union find graph
1598	Crawler Log Folder	Easy	TypeScript	array string stack
1605	Find Valid Matrix Given Row and Column Sums	Medium	TypeScript	array greedy matrix
1608	Special Array with X Elements Greater Than or Equal X	Easy	TypeScript	array binary search sorting
1679	Max Number of K Sum Pairs	Medium	TypeScript	array hash table two pointers sorting
1701	Average Waiting Time	Medium	TypeScript	array simulation
1717	Maximum Score from Removing Substrings	Medium	TypeScript	string stack greedy
1732	Find the Highest Altitude	Easy	TypeScript	array prefix sum
1768	Merge Strings Alternately	Easy	TypeScript	two pointers string
1791	Find Center of Star Graph	Easy	TypeScript	graph
1823	Find the Winner of the Circular Game	Medium	TypeScript	array math recursion queue simulation
1860	Incremental Memory Leak	Medium	TypeScript	math simulation

2000-2499

#	Problem	Difficulty	Language	Topics
2037	Minimum Number of Moves to Seat Everyone	Easy	TypeScript	array greedy sorting
2057	Smallest Index with Equal Value	Easy	JavaScript	array
2058	Find the Minimum and Maximum Number of Nodes Between Critical Points	Medium	TypeScript	linked list
2096	Step-By-Step Directions From a Binary Tree Node to Another	Medium	TypeScript	string tree depth-first search binary tree
2114	Maximum Number of Words Found in Sentences	Easy	TypeScript	array string
2181	Merge Nodes in Between Zeros	Medium	TypeScript	linked list simulation
2191	All Ancestors of a Node in a Directed Acyclic Graph	Medium	TypeScript	depth-first search breadth-first search graph topological sort
2196	Create Binary Tree From Descriptions	Medium	TypeScript	array hash table tree binary tree
2215	Find the Difference of Two Arrays	Easy	TypeScript	array hash table
2285	Maximum Total Importance of Roads	Medium	TypeScript	greedy graph sorting heap (priority queue)
2300	Successful Pairs of Spells and Potions	Medium	TypeScript	array two pointers binary search sorting
2390	Removing Stars from a String	Medium	TypeScript	string stack simulation
2392	Build a Matrix with Conditions	Hard	TypeScript	array graph topological sort matrix
2404	Most Frequent Even Element	Easy	TypeScript	array hash table counting
2486	Append Characters to String to Make Subsequence	Medium	TypeScript	two pointers string greedy

2500-2999

#	Problem	Difficulty	Language	Topics
2582	Pass the Pillow	Easy	TypeScript	math simulation
2605	Form Smallest Number from Two Digit Arrays	Easy	TypeScript	array hash table enumeration
2619	Array Prototype Last	Easy	JavaScript
2620	Counter	Easy	JavaScript
2626	Array Reduce Transformation	Easy	JavaScript
2634	Filter Elements From Array	Easy	JavaScript
2635	Apply Transform Over Each Element in Array	Easy	JavaScript
2665	Counter II	Easy	JavaScript
2667	Create Hello World Function	Easy	JavaScript
2704	To Be or Not To Be	Easy	JavaScript
2723	Add Two Promises	Medium	TypeScript
2727	Is Object Empty	Easy	JavaScript
2751	Robot Collisions	Hard	TypeScript	array stack sorting simulation

3000+

#	Problem	Difficulty	Language	Topics
3110	Score of a String	Easy	TypeScript	string