LeetCode

Resources

1. AlgoMonster - Questions/subjetcs patterns in coding interviews.
   • Includes specific data for Amazon, Apple, Google, Meta.
   • Includes ROI for different subjects in terms of time investments.
   • Flow chart of how to approach a problem.
   • Honestly, a lot more.
2. InterviewBit - Similar to LeetCode.
   • Shows company questions for free.
   • Has a focus on timing solutions.
3. NeetCode.io, NeetCode YouTube channel.
   • Subjects roadmap for learning and practicing.
   • NeetCode 75 & NeetCode 150 for interview preparations.
   • Videos of detailed solutions with explanations - both intuitively and programmatically.
   • Strategy of learning and solving LeetCode questions.

Solutions

Leetcode Profile

Solutions to the LeetCode problems I solved/studied so far:

Arrays & Hashing

#	Title	Solution	Difficulty	Notes
1	Two Sum	Python	Easy
41	First Missing Positive	Java, C	Hard	Time Complexity: O(n) Space Complexity: O(1)
49	Group Anagrams	Python	Medium
128	Longest Consecutive Sequence	Python	Hard
217	Contains Duplicate	Python	Easy
242	Valid Anagram	Python	Easy
2206	Divide Array Into Equal Pairs	Python	Easy

Sliding Window

#	Title	Solution	Difficulty	Notes
3	Longest Substring Without Repeating Characters	Python	Medium
424	Longest Repeating Character Replacement	Python	Medium

Binary Search

#	Title	Solution	Difficulty	Notes
4	Median of Two Sorted Arrays	Java	Hard	Explanation
33	Search in Rotated Sorted Array	Java	Medium
74	Search a 2D Matrix	Python	Medium

Two Pointers

#	Title	Solution	Difficulty	Notes
11	Container With Most Water	Python	Medium
15	3Sum	Python	Medium
125	Valid Palindrome	Python	Easy
167	Two Sum II - Input array is sorted	Python	Easy
1813	Sentence Similarity III	Python	Medium

Backtracking

#	Title	Solution	Difficulty	Notes
17	Letter Combinations of a Phone Number	Python	Medium
39	Combination Sum	Python	Medium
40	Combination Sum II	Python	Medium
46	Permutations	Python	Medium
78	Subsets	Python	Medium	Backtracking
79	Word Search	Python	Medium
90	Subsets II	Python	Medium
131	Palindrome Partitioning	Python	Medium
212	Word Search II	Python	Hard
1863	Sum of All Subset XOR Totals	Java	Easy

Linked List

#	Title	Solution	Difficulty	Notes
21	Merge Two Sorted Lists	Python	Easy
138	Copy List with Random Pointer	Python	Medium
141	Linked List Cycle	Python	Easy
206	Reverse Linked List	Python	Easy
287	Find the Duplicate Number	Python	Medium	Floyd's Tortoise and Hare (Cycle Detection)

Stack

#	Title	Solution	Difficulty	Notes
22	Generate Parentheses	Python	Medium
155	Min Stack	Python	Easy
739	Daily Temperatures	Python	Medium	Monotonic Stack
853	Car Fleet	Python	Medium

Greedy

#	Title	Solution	Difficulty	Notes
53	Maximum Subarray	Python	Medium
55	Jump Game	Python	Medium
134	Gas Station	Python	Medium

Intervals

#	Title	Solution	Difficulty	Notes
57	Insert Interval	Python	Medium

Dynamic Programming

#	Title	Solution	Difficulty	Notes
62	Unique Paths	Python	Medium
70	Climbing Stairs	Python	Easy
97	Interleaving String	Python	Medium
115	Distinct Subsequences	Python	Hard
139	Word Break	Python	Medium
198	House Robber	Python	Medium
213	House Robber II	Python	Medium	Circular Array
322	Coin Change	Python, Python	Medium	Brute Force, Top Down DP
416	Partition Equal Subset Sum	Python	Medium
494	Target Sum	Python	Medium	Subset Sum Problem
518	Coin Change II	Python	Medium
647	Palindromic Substrings	Python	Medium
746	Min Cost Climbing Stairs	Python	Easy
1143	Longest Common Subsequence	Python	Medium

Tree

#	Title	Solution	Difficulty	Notes
100	Same Tree	Python	Easy
102	Binary Tree Level Order Traversal	Python	Medium	BFS
104	Maximum Depth of Binary Tree	Python	Easy
226	Invert Binary Tree	Python	Easy
230	Kth Smallest Element in a BST	Python	Medium	Inorder Traversal
235	Lowest Common Ancestor of a Binary Search Tree	Python	Medium
1448	Count Good Nodes in Binary Tree	Python	Medium

Graph

#	Title	Solution	Difficulty	Notes
130	Surrounded Regions	Python	Medium
133	Clone Graph	Python	Medium
200	Number of Islands	Python	Medium
286	Walls and Gates	Python	Medium	Multi-Source BFS
329	Longest Increasing Path in a Matrix	Python	Hard
695	Max Area of Island	Python, Python	Medium	DFS, BFS
994	Rotting Oranges	Python	Medium

Bit Manipulation

#	Title	Solution	Difficulty	Notes
136	Single Number	Python	Easy	XOR

Heap / Priority Queue

#	Title	Solution	Difficulty	Notes
215	Kth Largest Element in an Array	Python	Medium	Quick Select
347	Top K Frequent Elements	Python	Medium
632	Smallest Range Covering Elements from K Lists	Python	Hard
703	Kth Largest Element in a Stream	Python	Easy
786	K-th Smallest Prime Fraction	Java	Medium
973	K Closest Points to Origin	Python	Medium
1046	Last Stone Weight	Python	Easy	Max Heap