16 CORE DSA PATTERNS

What if I told you that weight training to achieve your dream physique is very similar to practicing dsa for landing that dream company. Moreover, like you start with lighter weights and increase to heavier weights , similarly you start with easy problems and move to difficult problems. And like you have exercises for every body part , similarly you problems for each pattern. And like you have a specific schedule to help you achieve your dream physique, similarly you have specific problems to achieve the dream company.

Pattern 1: Sliding Window

Pattern 2: Two Pointer

Pattern 3: Fast & Slow pointers

Pattern 4: Merge Intervals

Pattern 5: Cyclic Sort

Pattern 6: In-place Reversal of a LinkedList

Pattern 7: Tree Breadth First Search

Pattern 8: Depth First Search (DFS)

Pattern 9: Two Heaps

Pattern 10: Subsets

Pattern 11: Modified Binary Search

Pattern 12: Bitwise XOR

Pattern 13: Top 'K' Elements

Pattern 14: K-way merge

Pattern 15: 0/1 Knapsack (Dynamic Programming)

Pattern 16: Topological Sort (Graph)

WEEK 1 : Two Pointers and Fast & Slow pointers

1. Introduction

2. Pair with Target Sum (easy) LeetCode

3. Remove Duplicates (easy) LeetCode LeetCode LeetCode LeetCode LeetCode

4. Squaring a Sorted Array (easy) LeetCode

5. Triplet Sum to Zero (medium) LeetCode

6. Triplet Sum Close to Target (medium) LeetCode

7. Triplets with Smaller Sum (medium) LintCode

8. Subarrays with Product Less than a Target (medium) LeetCode

9. Dutch National Flag Problem (medium) CoderByte

10. Problem Challenge 1: Quadruple Sum to Target (medium) Leetcode

11. Problem Challenge 2: Comparing Strings containing Backspaces (medium) Leetcode

12. Problem Challenge 3: Minimum Window Sort (medium) Leetcode Ideserve

13. Introduction emre.me

14. LinkedList Cycle (easy) Leetcode

15. Start of LinkedList Cycle (medium) Leetcode

16. Happy Number (medium) Leetcode

17. Middle of the LinkedList (easy) Leetcode

18. Problem Challenge 1: Palindrome LinkedList (medium) Leetcode

19. Problem Challenge 2: Rearrange a LinkedList (medium) Leetcode

20. Problem Challenge 3: Cycle in a Circular Array (hard) Leetcode

WEEK 2: Sliding Window and Merge Intervals

1. Introduction

2. Maximum Sum Subarray of Size K (easy)

3. Smallest Subarray with a given sum (easy) Educative.io

4. Longest Substring with K Distinct Characters (medium) Educative.io

5. Fruits into Baskets (medium) LeetCode

6. No-repeat Substring (hard) LeetCode

7. Longest Substring with Same Letters after Replacement (hard) LeetCode

8. Longest Subarray with Ones after Replacement (hard) LeetCode

9. Problem Challenge 1: Permutation in a String (hard) Leetcode

10. Problem Challenge 2: String Anagrams (hard) Leetcode

11. Problem Challenge 3: Smallest Window containing Substring (hard) Leetcode

12. Problem Challenge 4: Words Concatenation (hard) Leetcode

13. Introduction Educative.io

14. Merge Intervals (medium) Educative.io

15. Insert Interval (medium) Educative.io

16. Intervals Intersection (medium) Educative.io

17. Conflicting Appointments (medium) Geeksforgeeks

18. Problem Challenge 1: Minimum Meeting Rooms (hard) Lintcode

19. Problem Challenge 2: Maximum CPU Load (hard) Geeksforgeeks

20. Problem Challenge 3: Employee Free Time (hard) CoderTrain

WEEK 3: Cyclic Sort and In-place reversal of Linked List

1. Introduction emre.me

2. Cyclic Sort (easy) Geeksforgeeks

3. Find the Missing Number (easy) Leetcode

4. Find all Missing Numbers (easy) Leetcode

5. Find the Duplicate Number (easy) Leetcode

6. Find all Duplicate Numbers (easy) Leetcode

7. Problem Challenge 1: Find the Corrupt Pair (easy) TheCodingSimplified

8. Problem Challenge 2: Find the Smallest Missing Positive Number (medium) Leetcode

9. Problem Challenge 3: Find the First K Missing Positive Numbers (hard) TheCodingSimplified

10. Introduction emre.me

11. Reverse a LinkedList (easy) Leetcode

12. Reverse a Sub-list (medium) Leetcode

13. Reverse every K-element Sub-list (medium) Leetcode

14. Problem Challenge 1: Reverse alternating K-element Sub-list (medium) Geeksforgeeks

15. Problem Challenge 2: Rotate a LinkedList (medium) Leetcode

WEEK 4: Hash Maps and Tree : BFS

1. Binary Tree Level Order Traversal (easy) Leetcode

2. Reverse Level Order Traversal (easy) Leetcode

3. Zigzag Traversal (medium) Leetcode

4. Level Averages in a Binary Tree (easy) Leetcode

5. Minimum Depth of a Binary Tree (easy) Leetcode

6. Maximum Depth of a Binary Tree (easy) Leetcode

7. Level Order Successor (easy) Geeksforgeeks

8. Connect Level Order Siblings (medium) Leetcode

9. Problem Challenge 1: Connect All Level Order Siblings (medium) Educative

10. Problem Challenge 2: Right View of a Binary Tree (easy) Leetcode

11. Binary Tree Path Sum (easy) Leetcode

12. All Paths for a Sum (medium) Leetcode

13. Sum of Path Numbers (medium) Leetcode

14. Path With Given Sequence (medium) Geeksforgeeks

15. Count Paths for a Sum (medium) Leetcode

16. Problem Challenge 1: Tree Diameter (medium) Leetcode

17. Problem Challenge 2: Path with Maximum Sum (hard) Leetcode

WEEK 5: Two Heaps and Subsets

1. Find the Median of a Number Stream (medium) Leetcode

2. Sliding Window Median (hard) Leetcode

3. Maximize Capital (hard) Leetcode

4. *Maximum Sum Combinations (medium) InterviewBit

5. Subsets (easy) Educative.io

6. Subsets With Duplicates (easy) Educative.io

7. Permutations (medium) Educative.io

WEEK 6: Modified Binary Search and Bitwise XOR

1. Order-agnostic Binary Search (easy) Geeksforgeeks

2. Ceiling of a Number (medium) Geeksforgeeks-Ceil Geeksforgeeks-Floor

3. Next Letter (medium) Leetcode

4. Number Range (medium) Leetcode

5. Search in a Sorted Infinite Array (medium) Leetcode

6. Minimum Difference Element (medium): Find the floor & ceil take the difference, minimum would be the ans

7. Bitonic Array Maximum (easy) Geeksforgeeks

8. Problem Challenge 1: Search Bitonic Array (medium) Leetcode

9. Problem Challenge 2: Search in Rotated Array (medium) Leetcode

10. Problem Challenge 3: Rotation Count (medium) Geeksforgeeks

11. *Search a 2D Matrix (medium) Leetcode

12. *Minimum Number of Days to Make m Bouquets (medium) Leetcode

13. *Koko Eating Bananas (medium) Leetcode

14. *Capacity To Ship Packages Within D Days (medium) Leetcode

15. *Median of Two Sorted Arrays (hard) Leetcode

16. Single Number (easy)

17. Two Single Numbers (medium)

18. Complement of Base 10 Number (medium)

19. Problem Challenge 1: Flip and Invert an Image (hard)

WEEK 7: Top K Elements and K-way Merge

1. Top 'K' Numbers (easy) Solution

2. Kth Smallest Number (easy)

3. 'K' Closest Points to the Origin (easy) Leetcode

4. Connect Ropes (easy)

5. Top 'K' Frequent Numbers (medium)

6. Frequency Sort (medium)

7. Kth Largest Number in a Stream (medium) Leetcode

8. Merge K Sorted Lists (medium) Leetcode

9. Kth Smallest Number in M Sorted Lists (Medium) Geeksforgeeks

10. Kth Smallest Number in a Sorted Matrix (Hard) Educative.io

WEEK 8: 0/1 Knapsack and Topological Sort

1. 0/1 Knapsack (medium) Geeksforgeeks

2. Equal Subset Sum Partition (medium) Leetcode

3. Subset Sum (medium) Geeksforgeeks

4. Minimum Subset Sum Difference (hard) Geeksforgeeks

5. Topological Sort (medium) Youtube

6. Tasks Scheduling (medium) Leetcode-Similar

7. Tasks Scheduling Order (medium) Leetcode-Similar

8. All Tasks Scheduling Orders (hard) Leetcode-Similar

9. Alien Dictionary (hard) Leetcode

10. Problem Challenge 1: Reconstructing a Sequence (hard) Leetcode

11. Problem Challenge 2: Minimum Height Trees (hard) Leetcode