sanchit2843/Datastructure-and-algorithms

Datastructures and algorithms Practice

The 1-month plan will cover the most essential topics, giving you broad exposure to common questions. The 3-month plan will deepen your understanding with more advanced topics and reinforce previous ones. The 6-month plan will aim for mastery, revisiting tricky concepts and refining problem-solving skills.

---

1-Month Plan (Goal: Cover key topics to be interview-ready)

Time Commitment: 1 hour daily, 7 days a week

Week 1: Arrays and Strings (High Priority)

• Concepts to Focus On: Basic operations, sliding window, two pointers, hashing with arrays.
• LeetCode Questions:
  • Day 1-2: Easy Problems
    • Two Sum
    • Best Time to Buy and Sell Stock
    • Move Zeroes
    • Contains Duplicate
  • Day 3-4: Medium Problems
    • 3Sum
    • Longest Substring Without Repeating Characters
    • Container With Most Water
  • Day 5-6: Sliding Window & Two Pointers
    • Longest Repeating Character Replacement
    • Minimum Size Subarray Sum
  • Day 7: Review Day
    • Re-attempt 1-2 problems you found difficult and revise the concepts.

Week 2: Linked Lists, Stacks, and Queues

• Concepts to Focus On: Basic operations, reversing a list, stack-based problems (e.g., parentheses).
• LeetCode Questions:
  • Day 1-2: Linked Lists (Easy & Medium)
    • Reverse Linked List
    • Merge Two Sorted Lists
    • Linked List Cycle
  • Day 3-4: Medium Linked List Problems
    • Remove Nth Node From End of List
    • Add Two Numbers
  • Day 5: Stacks and Queues (Easy & Medium)
    • Valid Parentheses
    • Implement Queue using Stacks
  • Day 6: Stack Problems (Medium)
    • Daily Temperatures
    • Min Stack
  • Day 7: Review Day
    • Revisit 1-2 problems that were challenging or unclear.

Week 3: Hash Maps, Binary Search, and Sorting

• Concepts to Focus On: Frequency counting, sorting algorithms, binary search implementation.
• LeetCode Questions:
  • Day 1-2: Hash Maps
    • Group Anagrams
    • Subarray Sum Equals K
  • Day 3-4: Binary Search (Easy & Medium)
    • Binary Search
    • Find Peak Element
    • Search in Rotated Sorted Array
  • Day 5-6: Sorting
    • Merge Intervals
    • Kth Largest Element in an Array
  • Day 7: Review Day
    • Attempt 1-2 difficult problems again.

Week 4: Introduction to Trees and Graphs

• Concepts to Focus On: Tree traversals, basic graph representation, DFS/BFS.
• LeetCode Questions:
  • Day 1-2: Trees (Easy)
    • Maximum Depth of Binary Tree
    • Same Tree
    • Invert Binary Tree
  • Day 3-4: Trees (Medium)
    • Binary Tree Level Order Traversal
    • Construct Binary Tree from Preorder and Inorder Traversal
  • Day 5: Graph Basics (Introduction)
    • Number of Islands
    • Flood Fill
  • Day 6: Graph Traversal
    • Clone Graph
  • Day 7: Review Day
    • Review tree and graph problems.

Now is a good time to study some of the patterns in the leet code questions and try to solve more advanced algorithm. You can start by targeting each pattern, doing 4-5 questions for each and then moving on to more complex problems once these patterns are covered.

https://hackernoon.com/14-patterns-to-ace-any-coding-interview-question-c5bb3357f6ed https://www.youtube.com/playlist?list=PL7g1jYj15RUOjoeZAJsWjwV8XUo9r0hwc https://www.youtube.com/watch?v=xo7XrRVxH8Y https://www.youtube.com/watch?v=DjYZk8nrXVY https://github.com/dipjul/Grokking-the-Coding-Interview-Patterns-for-Coding-Questions

Mock Interviews and Testing (During Week 4)

• Day 5: Attempt one full-length mock interview on LeetCode, focusing on the problems covered so far.

---

3-Month Plan (Goal: Deepen understanding and refine skills)

Focus: Next 2 months; the first month is already completed.

Month 2 - Advanced Data Structures and Algorithms

• Week 5: Advanced Linked Lists and Introduction to Heaps

  • Concepts: Cycle detection, heap operations.
  • LeetCode Questions:
    • Linked List Cycle II
    • LRU Cache
    • Merge k Sorted Lists
    • Top K Frequent Elements

• Week 6: Dynamic Programming (Intro)

  • Concepts: Memoization, tabulation.
  • LeetCode Questions:
    • Climbing Stairs
    • House Robber
    • Coin Change
    • Longest Increasing Subsequence

• Week 7: Trees (In-Depth)

  • Concepts: Binary search trees, tree traversals.
  • LeetCode Questions:
    • Validate Binary Search Tree
    • Kth Smallest Element in a BST
    • Serialize and Deserialize Binary Tree

• Week 8: Graph Algorithms (Medium Level)

  • Concepts: DFS, BFS, shortest path.
  • LeetCode Questions:
    • Course Schedule
    • Word Ladder
    • Pacific Atlantic Water Flow

• Mock Interviews: Take 2 full-length mock interviews this month on LeetCode or other platforms.

Month 3 - Backtracking and Dynamic Programming (Advanced)

• Week 9: Backtracking

  • Concepts: Permutations, combinations, and pathfinding.
  • LeetCode Questions:
    • Permutations
    • Subsets
    • Word Search
    • N-Queens

• Week 10: Advanced Dynamic Programming

  • LeetCode Questions:
    • Edit Distance
    • Partition Equal Subset Sum
    • Longest Palindromic Substring

• Week 11: Graphs (Advanced)

  • LeetCode Questions:
    • Network Delay Time
    • [Cheapest Flights Within K Stops](https://leetcode

.com/problems/cheapest-flights-within-k-stops/)

• Week 12: Review and Mock Interviews
  • Review all problems covered in the past two months.
  • Take 2-3 mock interviews focusing on the comprehensive set of topics.

---

6-Month Plan (Goal: Mastery and high performance)

Focus: Final 3 months, refining problem-solving skills and tackling advanced topics.

Month 4-5 - Refinement and Advanced Topics

• Week 13-15: Deepen knowledge in graph algorithms (shortest paths, minimum spanning trees).
• Week 16-17: Practice complex dynamic programming problems.
• Week 18: Participate in coding contests on LeetCode to simulate pressure.

Month 6 - Mastery and Final Review

• Review: Revisit the hardest problems you've encountered. Focus on weaknesses.
• Mock Interviews: Conduct weekly mock interviews, simulating real pressure.