Mastering the Blind 75 LeetCode Questions: A Comprehensive Strategy for Coding Interviews

Introduction

LeetCode is a treasure trove of coding challenges that aid software engineers in preparing for technical interviews. Among its vast array of problems, the “Blind 75" is a curated list of questions that hold immense significance in interview preparation. In this article, we will delve into the Blind 75 questions, categorize them by topic, and provide a strategic approach to tackle these challenges effectively.

The Blind 75 Questions: A Diverse Set

The Blind 75 represents a carefully selected set of questions from LeetCode that have historically been encountered in coding interviews at prominent technology companies. These questions are revered for their diversity and the depth of knowledge they require in various algorithms and data structures. They encompass a wide range of topics, and to help you prepare, we’ve categorized them as follows:

### Arrays and Strings (15 questions)

1. Two Sum
2. 2. Best Time to Buy and Sell Stock
3. 3. Longest Substring Without Repeating Characters
4. 4. Container With Most Water
5. 5. 3Sum
6. 6. 3Sum Closest
7. 7. 4Sum
8. 8. Missing Positive
9. 9. Find First and Last Position of Element in Sorted Array
10. 10. Maximum Subarray
11. 11. Trapping Rain Water
12. 12. Product of Array Except Self
13. 13. Maximum Product Subarray
14. 14. Minimum Size Subarray Sum
15. 15. Minimum Window Substring

### Linked Lists (6 questions)

16. Reverse Linked List

17. Merge Two Sorted Lists

18. Merge k Sorted Lists

19. Swap Nodes in Pairs

20. Reverse Nodes in k-Group

21. Copy List with Random Pointer

### Binary Trees (12 questions)

22. Validate Binary Search Tree

23. Symmetric Tree

24. Maximum Depth of Binary Tree

25. Convert Sorted Array to Binary Search Tree

26. Lowest Common Ancestor of a Binary Tree

27. Serialize and Deserialize Binary Tree

28. Subtree of Another Tree

29. Construct Binary Tree from Preorder and Inorder Traversal

30. Populating Next Right Pointers in Each Node

31. Sum Root to Leaf Numbers

32. Path Sum

33. Flatten Binary Tree to Linked List

### Dynamic Programming (12 questions)

34. Climbing Stairs

35. Min Cost Climbing Stairs

36. Coin Change

37. Longest Increasing Subsequence

38. Longest Palindromic Substring

39. Regular Expression Matching

40. Wildcard Matching

41. Jump Game

42. Unique Paths

43. Minimum Path Sum

44. House Robber

45. Maximum Subarray

### Miscellaneous (15 questions)

46. Reverse Integer

47. Palindrome Number

48. Roman to Integer

49. Longest Common Prefix

50. Valid Parentheses

51. Generate Parentheses

52. Merge Intervals

53. Spiral Matrix

54. First Missing Positive

55. Find the Duplicate Number

56. Pow(x, n)

57. Subarray Sum Equals K

58. Container With Most Water

59. Longest Consecutive Sequence

60. Valid Sudoku

### Graphs and Search (15 questions)

61. Number of Islands

62. Course Schedule

63. Alien Dictionary

64. Number of Connected Components in an Undirected Graph

65. Longest Increasing Path in a Matrix

66. Clone Graph

67. Word Ladder

68. Word Ladder II

69. Surrounded Regions

70. Graph Valid Tree

71. Perfect Squares

72. Super Ugly Number

73. Ugly Number II

74. Word Search

75. Word Search II

Strategy to Tackle the Blind 75

1. **Understand the Categories**: Categorizing the questions is the first step. Focus on a category at a time and master its concepts.

2. **Start with the Easier Ones**: Begin with easier questions within each category to build your confidence.

3. **Analyze Patterns**: Recognize common patterns in problems as you solve them. This will help you identify efficient solutions.

4. **Practice on Paper or Whiteboard**: Simulate interview conditions by solving problems on paper or a whiteboard.

5. **Optimize Solutions**: Strive to optimize your code for time and space complexity.

6. **Track Your Progress**: Keep a record of questions you’ve solved and your thought process.

7. **Engage with the Community**: Leverage forums and discussions for different perspectives.

8. **Time Management**: Practice under time constraints to simulate real interviews.

9. **Repetition**: Regularly revisit the Blind 75 questions to reinforce your understanding.

Conclusion

The Blind 75 questions on LeetCode present a formidable challenge for coding interview preparation. By categorizing the questions, practicing systematically, and refining your problem-solving skills, you can significantly enhance your readiness for technical interviews at leading tech companies. The key to success lies in persistence and dedication. Good luck on your journey to mastering these questions, and may you shine in your coding interviews!