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20 plus coding pattern for programming.pdf
- 1. 20+ Coding Patterns tocrack any Coding Interviews DesignGurus.io
- 2. ➡What if youdon’t like to solve 100s of coding questions before your interview? ➡Don’t just LeetCode; follow these 23 Coding Patterns instead. DesignGurus.io
- 3. Usage: This algorithmictechnique is used when we need to handle the input data in a specific window size. Sliding Window 1. DS Involved: Array, String, HashTable Longest Substring with 'K' Distinct Characters Fruits into Baskets Sample Problems: DesignGurus.io
- 4. Usage: This patterndescribes all the efficient ways of traversing a matrix (or 2D array). 2. Islands (Matrix Traversal) DS Involved: Matrix, Queue Number of Islands Flood Fill Cycle in a Matrix Sample Problems: DesignGurus.io
- 5. Usage: This techniqueuses two pointers to iterate input data. Generally, both pointers move in the opposite direction at a constant interval. 3. Two Pointers DS Involved: Array, String, LinkedList Squaring a Sorted Array Dutch National Flag Problem Minimum Window Sort Sample Problems: DesignGurus.io
- 6. Usage: Also knownas Hare & Tortoise algorithm. This technique uses two pointers that traverse the input data at different speeds. 4. Fast & Slow Pointers DS Involved: Array, String, LinkedList Middle of the LinkedList Happy Number Cycle in a Circular Array Sample Problems: DesignGurus.io
- 7. Usage: This techniqueis used to deal with overlapping intervals. 5. Merge Intervals DS Involved: Array, Heap Conflicting Appointments Minimum Meeting Rooms Sample Problems: DesignGurus.io
- 8. Usage: Use thistechnique to solve array problems where the input data lies within a fixed range. 6. Cyclic Sort DS Involved: Array Find all Missing Numbers Find all Duplicate Numbers Find the First K Missing Positive Numbers Sample Problems: DesignGurus.io
- 9. Usage: This techniquedescribes an efficient way to reverse the links between a set of nodes of a LinkedList. Often, the constraint is that we need to do this in-place, i.e., using the existing node objects and without using extra memory. 7. In-place Reversal of a LinkedList DS Involved: LinkedList Reverse every K-element Sub-list Rotate a LinkedList Sample Problems: DesignGurus.io
- 10. Usage: This techniqueis used to solve problems involving traversing trees or graphs in a breadth-first search manner. 8. Breadth-First Search DS Involved: Tree, Graph, Matrix, Queue Binary Tree Level Order Traversal Minimum Depth of a Binary Tree Connect Level Order Siblings Sample Problems: DesignGurus.io
- 11. Usage: This techniqueis used to solve problems involving traversing trees or graphs in a depth-first search manner. 9. Depth First Search DS Involved: Tree, Graph, Matrix Path With Given Sequence Count Paths for a Sum Sample Problems: DesignGurus.io
- 12. Usage: In manyproblems, we are given a set of elements that can be divided into two parts. We are interested in knowing the smallest element in one part and the biggest element in the other part. As the name suggests, this technique uses a Min-Heap to find the smallest element and a Max-Heap to find the biggest element. 10. Two Heaps DS Involved: Heap, Array Find the Median of a Number Stream Next Interval Sample Problems: DesignGurus.io
- 13. Usage: Use thistechnique when the problem asks to deal with permutations or combinations of a set of elements. 11. Subsets DS Involved: Queue, Array, String String Permutations by changing case Unique Generalized Abbreviations Sample Problems: DesignGurus.io
- 14. Usage: Use thistechnique to search a sorted set of elements efficiently. 12. Modified Binary Search DS Involved: Array Ceiling of a Number Bitonic Array Maximum Sample Problems: DesignGurus.io
- 15. Usage: This techniqueuses the XOR operator to manipulate bits to solve problems. 13. Bitwise XOR DS Involved: Array, Bits Two Single Numbers Flip and Invert an Image Sample Problems: DesignGurus.io
- 16. Usage: This techniqueis used to find top/smallest/frequently occurring ‘K’ elements in a set. 14. Top ‘K’ Elements DS Involved: Array, Heap, Queue ‘K’ Closest Points to the Origin Maximum Distinct Elements Sample Problems: DesignGurus.io
- 17. Usage: This techniquehelps us solve problems that involve a list of sorted arrays. 15. K-way Merge DS Involved: Array, Queue, Heap Kth Smallest Number in M Sorted Lists Kth Smallest Number in a Sorted Matrix Sample Problems: DesignGurus.io
- 18. Usage: This techniqueis used to solve optimization problems. Use this technique to select elements that give maximum profit from a given set with a limitation on capacity and that each element can only be picked once. 16. 0/1 Knapsack DS Involved: Array, HashTable Equal Subset Sum Partition Minimum Subset Sum Difference Sample Problems: DesignGurus.io
- 19. Usage: Use thistechnique to select elements that give maximum profit from a given set with a limitation on capacity and that each element can be picked multiple times. 17. Unbounded Knapsack DS Involved: Array, HashTable Rod Cutting Coin Change Sample Problems: DesignGurus.io
- 20. Usage: Use thistechnique to solve problems that follow the Fibonacci numbers sequence, i.e., every subsequent number is calculated from the last few numbers. 18. Fibonacci Numbers DS Involved: Array, HashTable Staircase House Thief Sample Problems: DesignGurus.io
- 21. Usage: This techniqueis used to solve optimization problems related to palindromic sequences or strings. 19. Palindromic Subsequence DS Involved: Array, HashTable Longest Palindromic Subsequence Minimum Deletions in a String to make it a Palindrome Sample Problems: DesignGurus.io
- 22. Usage: Use thistechnique to find the optimal part of a string/sequence or set of strings/sequences. 20. Longest Common Substring DS Involved: Array, HashTable Maximum Sum Increasing Subsequence Edit Distance Sample Problems: DesignGurus.io
- 23. Usage: Use thistechnique to find a linear ordering of elements that have dependencies on each other. 21. Topological Sort DS Involved: Array, HashTable, Queue, Graph Tasks Scheduling Alien Dictionary Sample Problems: DesignGurus.io
- 24. Usage: Use thistechnique to build a solution incrementally and follow the approach that if the current solution can’t lead to a valid solution, abandon it and backtrack (or go back) to try another solution. 22. Backtracking DS Involved: Array, HashTable, LinkedList Combination Sum Sudoku Solver Sample Problems: DesignGurus.io
- 25. Usage: Make youralgorithm multi-threaded to perform multiple concurrent tasks or to perform pre-fetching or post-processing functions to speed things up. 23. Multi-threaded Same Tree Invert Binary Tree Binary Search Tree Iterator Sample Problems: DesignGurus.io
- 26. ➡Follow these techniquesto distinguish yourself from others! ➡All these patterns are discussed in "Grokking the Coding Interview" and "Grokking Dynamic Programming" from DesignGurus.io DesignGurus.io