Amazon Medium Problems sorted by frequency

1. LRU Cache
2. Maximum Frequency After Subarray Operation
3. Number of Islands
4. Reorganize String
5. Longest Palindromic Substring
6. Maximize Y‑Sum by Picking a Triplet of Distinct X‑Values
7. Add Two Numbers
8. Find First and Last Position of Element in Sorted Array
9. Koko Eating Bananas
10. Jump Game II
11. Group Anagrams
12. Longest Substring Without Repeating Characters
13. House Robber
14. Top K Frequent Elements
15. Generate Parentheses
16. Merge Intervals
17. Search a 2D Matrix
18. Best Time to Buy and Sell Stock II
19. Min Stack
20. Longest Repeating Character Replacement
21. Next Permutation
22. Search in Rotated Sorted Array
23. Course Schedule II
24. Meeting Rooms II
25. Coin Change
26. Number of Connected Components in an Undirected Graph
27. Rotting Oranges
28. Using a Robot to Print the Lexicographically Smallest String
29. String to Integer (atoi)
30. Integer to Roman
31. 3Sum
32. Rotate Image
33. Maximum Subarray
34. Unique Paths
35. Edit Distance
36. Word Search
37. Binary Tree Right Side View
38. Kth Largest Element in an Array
39. Lowest Common Ancestor of a Binary Tree
40. Product of Array Except Self
41. Subarray Sum Equals K
42. Top K Frequent Words
43. Analyze User Website Visit Pattern
44. Count the Number of Substrings With Dominant Ones
45. Valid Sudoku
46. Combination Sum
47. Jump Game
48. Decode Ways
49. Validate Binary Search Tree
50. Reorder List
51. Evaluate Reverse Polish Notation
52. Find Minimum in Rotated Sorted Array
53. Course Schedule
54. Find the Duplicate Number
55. Design Tic-Tac-Toe
56. Insert Delete GetRandom O(1)
57. Pacific Atlantic Water Flow
58. String Compression
59. Number of Provinces
60. Maximize Distance to Closest Person
61. Capacity To Ship Packages Within D Days
62. Lexicographically Smallest Equivalent String
63. Max Difference You Can Get From Changing an Integer
64. Minimum Equal Sum of Two Arrays After Replacing Zeros
65. Lexicographically Minimum String After Removing Stars
66. Zigzag Conversion
67. Reverse Integer
68. Container With Most Water
69. Spiral Matrix
70. Rotate List
71. Unique Paths II
72. Simplify Path
73. Subsets
74. Recover Binary Search Tree
75. Binary Tree Level Order Traversal
76. Construct Binary Tree from Preorder and Inorder Traversal
77. Triangle
78. Longest Consecutive Sequence
79. Find Peak Element
80. Rotate Array
81. Implement Trie (Prefix Tree)
82. Maximal Square
83. Basic Calculator II
84. Kth Smallest Element in a BST
85. Find the Celebrity
86. Binary Tree Vertical Order Traversal
87. House Robber III
88. Decode String
89. Evaluate Division
90. Target Sum
91. Next Greater Element II
92. Coin Change II
93. Random Pick with Weight
94. Single Element in a Sorted Array
95. Task Scheduler
96. Max Area of Island
97. Asteroid Collision
98. Daily Temperatures
99. K-th Symbol in Grammar
100. Find Eventual Safe States
101. Snakes and Ladders
102. Subarray Sums Divisible by K
103. Time Based Key-Value Store
104. Max Consecutive Ones III
105. Parallel Courses
106. Longest Continuous Subarray With Absolute Diff ≤ Limit
107. Magnetic Force Between Two Balls
108. Finding the Users Active Minutes
109. Plates Between Candles
110. Find All Possible Recipes from Given Supplies
111. Count Zero Request Servers
112. Distribute Candies Among Children II

Category Based DS:

Array

1. Maximum Frequency After Subarray Operation
2. Find First and Last Position of Element in Sorted Array
3. Koko Eating Bananas
4. Jump Game II
5. Maximum Subarray
6. Product of Array Except Self
7. Maximize Distance to Closest Person
8. Daily Temperatures
9. Spiral Matrix
10. Container With Most Water
11. Next Greater Element II
12. Subarray Sum Equals K
13. Subarray Sums Divisible by K
14. Max Consecutive Ones III
15. Minimum Equal Sum of Two Arrays After Replacing Zeros
16. Lexicographically Minimum String After Removing Stars
17. Longest Continuous Subarray With Absolute Diff ≤ Limit

String

1. Longest Palindromic Substring
2. Reorganize String
3. String to Integer (atoi)
4. Integer to Roman
5. Zigzag Conversion
6. Rotate String
7. String Compression
8. Decode String

Graph

1. Number of Islands
2. Pacific Atlantic Water Flow
3. Number of Connected Components in an Undirected Graph
4. Course Schedule
5. Course Schedule II
6. Snakes and Ladders
7. Find All Possible Recipes from Given Supplies
8. Parallel Courses
9. Find Eventual Safe States

Heap / Priority Queue

1. Top K Frequent Elements
2. Top K Frequent Words
3. Kth Largest Element in an Array
4. Task Scheduler
5. Maximize Y‑Sum by Picking a Triplet of Distinct X‑Values

Tree / Binary Tree

1. Binary Tree Right Side View
2. Lowest Common Ancestor of a Binary Tree
3. Binary Tree Level Order Traversal
4. Construct Binary Tree from Preorder and Inorder Traversal
5. Kth Smallest Element in a BST
6. Recover Binary Search Tree
7. Diameter of Binary Tree
8. Binary Tree Vertical Order Traversal
9. House Robber III

Linked List

1. Add Two Numbers
2. Rotate List
3. Reorder List

Sliding Window

1. Longest Substring Without Repeating Characters
2. Longest Repeating Character Replacement
3. Max Consecutive Ones III
4. Longest Continuous Subarray With Absolute Diff ≤ Limit

Dynamic Programming (DP)

1. House Robber
2. Unique Paths
3. Triangle
4. Edit Distance
5. Decode Ways
6. Coin Change
7. Coin Change II
8. Maximal Square

Backtracking

1. Generate Parentheses
2. Word Search
3. Combination Sum
4. Subsets

Design

1. LRU Cache
2. Insert Delete GetRandom O(1)
3. Time Based Key-Value Store
4. Random Pick with Weight
5. Design Tic-Tac-Toe

Math / Logic

1. Evaluate Reverse Polish Notation
2. Evaluate Division
3. Basic Calculator II
4. Analyze User Website Visit Pattern

Uncategorized

(less conventional patterns or hybrid logic-heavy problems)

1. Using a Robot to Print the Lexicographically Smallest String
2. Analyze User Website Visit Pattern
3. Count the Number of Substrings With Dominant Ones
4. Lexicographically Smallest Equivalent String
5. Max Difference You Can Get From Changing an Integer
6. Word Search II
7. Find the Duplicate Number
8. Alien Dictionary
9. Plates Between Candles
10. Count Zero Request Servers
11. Distribute Candies Among Children II