Top Leetcode Patterns to Use for FAANG Coding Interviews

Top Leetcode Patterns to Use for FAANG Coding Interviews

Preparing for coding interviews can be made easier by focusing on coding patterns, especially those in LeetCode. Every software engineer should learn coding patterns such as Sliding Window, Two Pointers, Two Heaps, etc. By doing so, software engineers can develop the skill of “mapping a new problem to an existing one.” In this post, we will learn which coding patterns have the highest return on investment for software engineers.

LeetCode Problems Distribution

LeetCode is the largest repository of coding problems, containing more than 2000 questions. Each question on LeetCode can be tagged with one or more topics. These topics are either data structures like Array, HashTable, Tree, etc., algorithmic techniques like Greedy, Divide and Conquer, Sorting, etc., or coding patterns like Sliding Window, Depth First Search, Topological Sort, etc.

The top topic is Array with 1142 problems, followed by String with 549 problems. Let’s take a closer look at each category of topics, namely Data Structures, Algorithms, and Coding Patterns.

Top Data Structures with best ROI

Here are the top Data Structures with the highest return on investment:

  1. Array (1142 problems)
  2. String (549)
  3. Hash Table (392)
  4. Tree (191)
  5. Matrix (171)
  6. Stack (128)
  7. Heap or Priority Queue (107)
  8. Graph (102)
  9. Linked List (69)
  10. Trie (44)

Top algorithmic techniques with the best ROI

Here are the top algorithmic techniques with the highest return on investment:

  1. Dynamic Programming (383)
  2. Sorting (253)
  3. Greedy (248)
  4. Binary Search (186)
  5. Backtracking (91)
  6. Recursion (44)
  7. Divide and Conquer (38)

Top coding patterns with the best ROI

Here are the top coding patterns with the highest return on investment:

  1. Depth First Search (250)
  2. Breadth First Search(198)
  3. Binary Search (186)
  4. Two Pointers (147)
  5. Sliding Window (72)
  6. Monotonic Stack (44)
  7. Union Find (63)
  8. Memoization (32)
  9. Topological Sort (28)
  10. Segment Tree (27)

Best coding patterns with the highest ROI

Combining all categories from the above data, here is the list of best coding patterns/techniques with the highest ROI:

1. Two Pointers (Arrays, Strings, Fast & Slow Pointer)

This pattern covers a vast set of questions related to Arrays and Strings, which are the highest tagged data structures. Fast & Slow Pointer can be easily understood as a variation of the Two Pointers pattern.

2. Sliding Window (Arrays, Strings, Hash Tables)

Sliding Window covers most of the problems related to top data structures like Arrays, Strings, and HashTables.

3. Tree and Graph Depth First Search (Matrix Traversal)

Most Trees and Graphs problems can be solved using Depth First Search (DFS). Matrix Traversal, which is also DFS based pattern, covers most of the matrix-related problems.

4. Tree and Graph Breadth First Search (Queue, Subsets, Matrix Traversal, Topological Sort)

Breadth First Search (BFS) is a very handy pattern. BFS patterns like Subsets, Matrix Traversal, and Topological Sort cover many problems.

5. Binary Search (Arrays)

Binary Search and its variants are used to solve many coding questions.

6. Interval Merge

Although there are not many problems related to Interval Merge, these problems frequently appear in coding interviews.

7. Recursion/Backtracking

Backtracking and recursion are used to solve a wide range of problems. Mastering these techniques is highly recommended.

Conclusion

Most programming interviews include LeetCode-type questions. Most software engineers practice such coding problems before interviews. The highest return on investment is achieved by preparing smartly and focusing on the problem patterns that are the most common.

This article was written by Arslan Ahmad for HackerNoon and was edited and published with permission.