Coding-Interview-Patterns

1. Pattern: Sliding Window

• Maximum Sum Subarray of Size K (easy)
• Smallest Subarray with a given sum (easy)
• Longest Substring with K Distinct Characters (medium)
• Fruits into Baskets (medium)
• No-repeat Substring (hard)
• Longest Substring with Same Letters after Replacement (hard)
• Longest Subarray with Ones after Replacement (hard)
• Problem Challenge 1 - Permutation in a String (hard)
• Problem Challenge 2 - String Anagrams (hard)
• Problem Challenge 3 - Smallest Window containing Substring (hard)
• Problem Challenge 4 - Words Concatenation (hard)

2. Pattern: Two Pointers

• Pair with Target Sum (easy)
• Remove Duplicates (easy)
• Squaring a Sorted Array (easy)
• Triplet Sum to Zero (medium)
• Triplet Sum Close to Target (medium)
• Triplets with Smaller Sum (medium)
• Subarrays with Product Less than a Target (medium)
• Problem Challenge 1 - Quadruple Sum to Target (medium)
• Problem Challenge 2 - Comparing Strings containing Backspaces (medium)
• Problem Challenge 3 - Minimum Window Sort (medium)

3. Pattern: Fast & Slow pointers

• LinkedList Cycle (easy)
• Middle of the LinkedList (easy)
• Start of LinkedList Cycle (medium) *
• Happy Number (medium) *
• Problem Challenge 1 - Palindrome LinkedList (medium) *
• Problem Challenge 2 - Rearrange a LinkedList (medium)
• Problem Challenge 3 - Cycle in a Circular Array (hard) *

4. Pattern: Merge Intervals

• Merge Intervals (medium)
• Insert Interval (medium) *
• Intervals Intersection (medium)
• Conflicting Appointments (medium)
• Problem Challenge 1 - Minimum Meeting Rooms (hard) *
• Problem Challenge 2 - Maximum CPU Load (hard)
• Problem Challenge 3 - Employee Free Time (hard) *

5.Pattern: Cyclic Sort

• Cyclic Sort (easy)
• Find the Missing Number (easy)
• Find all Missing Numbers (easy)
• Find the Duplicate Number (easy)
• Find all Duplicate Numbers (easy)
• Problem Challenge 1 - Find the Corrupt Pair (easy)
• Prob lem Challenge 2 - Find the Smallest Missing Positive Number (medium)
• Problem Challenge 3 - Find the First K Missing Positive Numbers (hard) *

6. Pattern: In-place Reversal of a LinkedList

• Reverse a LinkedList (easy)
• Reverse a Sub-list (medium)
• Reverse every K-element Sub-list (medium) *
• Problem Challenge 1 - Reverse alternating K-element Sub-list (medium)
• Problem Challenge 2 - Rotate a LinkedList (medium)

7. Pattern: Tree Breadth First Search

• Binary Tree Level Order Traversal (easy)
• Reverse Level Order Traversal (easy) *
• Zigzag Traversal (medium)
• Level Averages in a Binary Tree (easy)
• Minimum Depth of a Binary Tree (easy)
• Level Order Successor (easy)
• Connect Level Order Siblings (medium)
• Problem Challenge 1 - Connect All Level Order Siblings (medium)
• Problem Challenge 2 - Right View of a Binary Tree (eas* y)

8. Pattern: Tree Depth First Search

• Binary Tree Path Sum (easy)
• All Paths for a Sum (medium)
• Sum of Path Numbers (medium)
• Path With Given Sequence (medium)
• Count Paths for a Sum (medium)
• Problem Challenge 1 - Tree Diameter (medium)
• Problem Challenge 2 - Path with Maximum Sum (hard)

9. Pattern: Two Heaps

• Find the Median of a Number Stream (medium)
• Sliding Window Median (hard)
• Maximize Capital (hard)
• Problem Challenge 1 - Next Interval (hard)

10. Pattern: Subsets

• Subsets (easy)
• Subsets With Duplicates (easy) *
• Permutations (medium) *
• String Permutations by changing case (medium)
• Balanced Parentheses (hard) *
• Unique Generalized Abbreviations (hard) *
• Problem Challenge 1 - Evaluate Expression (hard) *
• Problem Challenge 2 - Structurally Unique Binary Search Trees (hard) *
• Problem Challenge 3 - Count of Structurally Unique Binary Search Trees (hard)

11. Pattern: Modified Binary Search

• Order-agnostic Binary Search (easy)
• Ceiling of a Number (medium)
• Next Letter (medium)
• Number Range (medium)
• Search in a Sorted Infinite Array (medium)
• Minimum Difference Element (medium)
• Bitonic Array Maximum (easy)
• Problem Challenge 1 - Search Bitonic Array (medium)
• Problem Challenge 2 - Search in Rotated Array (medium)
• Problem Challenge 3 - Rotation Count (medium)

12. Pattern: Bitwise XOR

• Single Number (easy)
• Two Single Numbers (medium)
• Complement of Base 10 Number (medium)
• Problem Challenge 1

13. Pattern Top 'K' Elements

• Top 'K' Numbers (easy)
• Kth Smallest Number (easy)
• 'K' Closest Points to the Origin (easy)
• Connect Ropes (easy)
• Top 'K' Frequent Numbers (medium)
• Frequency Sort (medium)
• Kth Largest Number in a Stream (medium)
• 'K' Closest Numbers (medium)
• Maximum Distinct Elements (medium)
• Sum of Elements (medium)
• Rearrange String (hard)
• Problem Challenge 1 - Rearrange String K Distance Apart (hard)
• Problem Challenge 2 - Scheduling Tasks (hard)
• Problem Challenge 3 - Frequency Stack (hard)

14. Pattern: K-way merge

• Merge K Sorted Lists (medium)
• Kth Smallest Number in M Sorted Lists (Medium)
• Kth Smallest Number in a Sorted Matrix (Hard)
• Smallest Number Range (Hard)
• Problem Challenge 1 - K Pairs with Largest Sums (Hard)

15. Pattern : 0/1 Knapsack (Dynamic Programming)

• 0/1 Knapsack (medium)
• Equal Subset Sum Partition (medium)
• Subset Sum (medium)
• Minimum Subset Sum Difference (hard)
• Problem Challenge 1 - Count of Subset Sum (hard)
• Problem Challenge 2 - Target Sum (hard)

16. Pattern: Topological Sort (Graph* )

• Topological Sort (medium)
• Tasks Scheduling (medium)
• Tasks Scheduling Order (medium)
• All Tasks Scheduling Orders (hard)
• Alien Dictionary (hard)
• Problem Challenge 1 - Reconstructing a Sequence (hard)
• Problem Challenge 2 - Minimum Height Trees (hard)

17. Miscellaneous

• Kth Smallest Number (hard) *