LeetCode problems based on problem solving techniques

Granular breakdown by subtechnique, focusing on patterns relevant to Amazon

🧠 Greedy Subpatterns

• Greedy for Local Min/Max
• 122. Best Time to Buy and Sell Stock II

1. Gas Station
2. Container With Most Water

• Greedy + Sorting
• 253. Meeting Rooms II

1. Queue Reconstruction by Height

• Greedy + PriorityQueue
• 621. Task Scheduler

1. Min Cost to Connect All Points

🔁 Two Pointers / Sliding Window Subpatterns

• Fixed-size Window
• 1004. Max Consecutive Ones III

1. Longest Subarray With Abs Diff ≤ Limit

• Variable-size Window
• 3. Longest Substring Without Repeating Characters

1. Minimum Window Substring

• Opposite Direction Pointers
• 11. Container With Most Water

1. Two Sum II

📈 Binary Search Subpatterns

• Search in Sorted Array
• 34. Find First and Last Position

1. Single Element in Sorted Array

• Search on Answer (Binary Search over solution space)
• 875. Koko Eating Bananas

1. Capacity To Ship Packages
2. Magnetic Force Between Balls

• Bitonic Array / Peak Finding
• 162. Find Peak Element

🧮 Dynamic Programming (DP) Subpatterns

• 0/1 Knapsack Style
• 494. Target Sum

1. Coin Change II

• DP on Sequences
• 300. Longest Increasing Subsequence

1. Decode Ways

• DP on Grid
• 62. Unique Paths

1. Maximal Square

• DP with State Transitions
• 72. Edit Distance

1. Longest Valid Parentheses

• Interval DP
• 1235. Job Scheduling

1. Burst Balloons

🌊 Graph / BFS / DFS Subpatterns

• Cycle Detection (Directed / Undirected)
• 207. Course Schedule

1. Number of Connected Components

• Topological Sort
• 210. Course Schedule II

1. Alien Dictionary

• Multi-source BFS
• 994. Rotting Oranges

1. Shortest Path Visiting All Nodes

• DFS for Components or Traversals
• 200. Number of Islands

1. Find Eventual Safe States

• Union-Find
• 547. Number of Provinces

1. Accounts Merge

🧮 Math / Bit Manipulation Subpatterns

• Bitmasking
• 421. Max XOR of Two Numbers in an Array

1. Subsets

• Digit-by-digit / Simulation
• 43. Multiply Strings

1. Add Binary

• Number Properties
• 136. Single Number

1. Majority Element

🗂️ Heap / PriorityQueue Subpatterns

• MinHeap for k elements / Top K
• 215. Kth Largest Element

1. Top K Frequent Elements

• Merge K Lists
• 23. Merge k Sorted Lists

1. Median from Data Stream

🔄 Backtracking Subpatterns

• Combinations & Subsets
• 39. Combination Sum

1. Subsets

• Permutations
• 46. Permutations

1. Permutations II

• Constraint Satisfaction
• 51. N-Queens

1. Sudoku Solver

• Word Building
• 212. Word Search II

1. Word Break II

📊 Stack Subpatterns

• Monotonic Stack (Next Greater)
• 739. Daily Temperatures

1. Next Greater Element II

• Expression Evaluation
• 224. Basic Calculator

1. Reverse Polish Notation

• Parentheses Matching
• 20. Valid Parentheses

1. Longest Valid Parentheses