If you want to solve problems based on the patterns most frequently asked in tech company interviews, then "Blind 75 & NeetCode 150" are for you.

1. Blind 75: List of the 75 essential LeetCode algorithms problems.(Curated by Yangshun, a former Meta staff engineer) Easy: 19, Medium: 49, Hard: 7.
2. NeetCode 150: Expands on Blind 75 with 75 more problems. Easy: 28, Medium: 101, Hard: 21.

"Blind 75" vs "NeetCode 150" -> Blind 75 offers a solid foundation with essential LeetCode problems But "NeetCode 150" expands this palette, covering a wider array of patterns and topics!

Recommended YouTube Channel for solving tutorials: "NeetCode"

Standard Time for Solving LeetCode Problems:

1. Easy: 15-20 minutes
2. Medium: 30 minutes
3. Hard: 40-60 minutes

DSA Topics and Problem Distribution:

1. Arrays & Hashing: NeetCode (9), Blind (8)
2. Two Pointers: NeetCode (5), Blind (3)
3. Sliding Window: NeetCode (6), Blind (4)
4. Stack: NeetCode (7), Blind (1)
5. Binary Search: NeetCode (7), Blind (2)
6. Linked List: NeetCode (11), Blind (6)
7. Trees: NeetCode (15), Blind (11)
8. Tries: NeetCode (3), Blind (3)
9. Heap / Priority Queue: NeetCode (7), Blind (1)
10. Backtracking: NeetCode (9), Blind (2)
11. Graphs: NeetCode (13), Blind (6)
12. Advanced Graphs: NeetCode (6), Blind (1)
13. 1-D Dp: NeetCode (12), Blind (10)
14. 2-D Dp: NeetCode (11), Blind (2)
15. Greedy: NeetCode (8), Blind (2)
16. Intervals: NeetCode (6), Blind (5)
17. Math & Geometry: NeetCode (8), Blind (3)
18. Bit Manipulation: NeetCode (7), Blind (5)

-> Here the problem topics are listed along with the number of problems in each topic. For example, there are 9 problems in Arrays & Hashing where Blind has 8, but NeetCode has 9, that means there are 8 common problems.

Important DSA: BFS & DFS, Sliding window, Top K elements, Linked list, Stack, Queue, DP, Array, String, Searching, Sorting, Backtracking, Trie, Bit manipulation, Graph, BST.

Some of the Most Important patterns that are frequently asked in Interviews and OAs:

1. Sliding Window (Fixed sized window and variable sized window questions on array and string)
2. Island problems(DFS/BFS or different traversals on grid)
3. Two Pointers, Fast and Slow pointer
4. Merge Intervals
5. Cyclic Sort(Very important)
6. DFS and BFS
7. Two Heaps Problems(Find median in a stream problem)
8. Subset Problems
9. Subarray/Substring problems using Hashing
10. Binary Search
11. Bitwise XOR(Common asked question in many OAs)
12. Top k elements
13. K way merge
14. Topological Sort
15. Bit Manipulation
16. Number Theory