Data-Structures-RoadMap

Data structures roadmap to solve 150+ leetcode problems in 5 weeks with a good understanding of basics and techniques

Some considerations while starting with problem-solving till 100+ Leetcode problems are solved:

• Start with the most-easiest problems.
• DO NOT try to solve each problem yourself, instead try to learn and understand how different problems are being solved
• Do not try to solve a problem for more than 1 hour initially to get fast and to achieve more in less time, for any problem taking more than 1 hour, put it in a backlog and solve it later
• Average time to solve a problem should be 30-45 minutes
• Do not try to solve a lot of problems from one topic, instead try to solve 5-10 problems per topic
• Do not try to jump into problem-solving directly without the necessary pre-requisites, For example

  If you are trying to solve a problem that requires HashSet/HashMap then make sure you have studied HashMap before solving the problem If you are trying to solve a problem that uses recursion, first make sure you learn recursion properly If you are trying to solve a problem that uses graphs/trees, first make sure you learn graphs/tree properly If you are trying to solve a problem that uses dynamic programming, first make sure you learn dynamic programming properly.

Week 1- Data Structures Overview:

• Basic Understanding of Data structures in your language (C++ STL, C# Collections, Python Standard Library)

• If you like C++ and more details > My code school Data Structures

  https://www.youtube.com/playlist?list=PL2_aWCzGMAwI3W_JlcBbtYTwiQSsOTa6P (C++)

• If you like Python > code basics - Data Structures

  https://www.youtube.com/playlist?list=PLeo1K3hjS3uu_n_a__MI_KktGTLYopZ12

• Introduction to Hash Tables and Dictionaries by CS Dojo:

  https://www.youtube.com/watch?v=sfWyugl4JWA

Week 2 - 25 EASY problems ( 3-4 hours a day | 4 problems a day):

• Easy String Algorithms

  1. String as character arrays:

     video: https://www.youtube.com/watch?v=TkTgo_7ab0M&pp=ygUQcHJpbnQgY2hhcmFjdGVycw%3D%3D

  2. Count characters in string

     video: https://www.youtube.com/watch?v=kWr0TIjO6nU

• Arrays & Hashing:_

  1. Contains Duplicate

     video: https://www.youtube.com/watch?v=3OamzN90kPg problem: https://leetcode.com/problems/contains-duplicate/

  2. Valid Anagram:

     video: https://www.youtube.com/watch?v=9UtInBqnCgA problem: https://leetcode.com/problems/valid-anagram

  3. Two Sum:

     video: https://www.youtube.com/watch?v=KLlXCFG5TnA problem: https://leetcode.com/problems/group-anagrams/

  4. Length of Last word:

     video: https://www.youtube.com/watch?v=KT9rltZTybQ&list=PLot-Xpze53lfQmTEztbgdp8ALEoydvnRQ&index=27 problem:

  5. Search Insert Position

     video: https://www.youtube.com/watch?v=K-RYzDZkzCI&list=PLot-Xpze53lfQmTEztbgdp8ALEoydvnRQ&index=23 problem:

• Two Pointers:_

  1. Valid Palindrome

     video: https://leetcode.com/problems/valid-palindrome/
     problem: https://leetcode.com/problems/valid-palindrome/

  2. Best time to buy and Sell Stock:

     video: https://www.youtube.com/watch?v=1pkOgXD63yU&list=PLot-Xpze53lfQmTEztbgdp8ALEoydvnRQ&index=7&pp=iAQB problem: https://leetcode.com/problems/best-time-to-buy-and-sell-stock/

• Stack & Queue Problems:_

  1. Valid Parenthesis

     video: https://www.youtube.com/watch?v=WTzjTskDFMg problem: https://leetcode.com/problems/valid-parentheses/

  2. Implement Stack using Queue:

     video: https://www.youtube.com/watch?v=rW4vm0-DLYc&list=PLot-Xpze53lfxD6l5pAGvCD4nPvWKU8Qo&index=10 problem: https://leetcode.com/problems/implement-stack-using-queues/

  3. Implement Queue using Stack:

     video: https://www.youtube.com/watch?v=3Et9MrMc02A&pp=ygUabmVldGNvZGUgcXVldWUgdXNpbmcgc3RhY2s%3D problem: https://leetcode.com/problems/implement-queue-using-stacks/

  4. Sqrt(x)

     problem: https://leetcode.com/problems/sqrtx/ video:

  5. 704 Binary Search

     problem: https://leetcode.com/problems/binary-search/ video:

  6. Count Negative Numbers in a Sorted Matrix

     problem: https://leetcode.com/problems/count-negative-numbers-in-a-sorted-matrix/ video:

  7. Peak Index in a Mountain Array

     • problem: https://leetcode.com/problems/peak-index-in-a-mountain-array/
     • video:

  8. Find Peak element:

     • video: https://www.youtube.com/watch?v=CFgUQUL7j_c
       • problem:

  9. Maximum Sub Array:

     • video: https://www.youtube.com/watch?v=5WZl3MMT0Eg&list=PLot-Xpze53lfQmTEztbgdp8ALEoydvnRQ&index=4
       • problem: https://leetcode.com/problems/maximum-subarray/

• Linked List Course:_

  course with problems (find all the similar problems on leetcode): video: https://www.youtube.com/watch?v=Hj_rA0dhr2I&pp=ygUXbGlua2VkbGlzdCBmcmVlY29kZWNhbXA%3D

• Linked list problems:_

  1. Reverse Linked List

     https://leetcode.com/problems/reverse-linked-list/ https://www.youtube.com/watch?v=G0_I-ZF0S38

  2. Merge 2 sorted Lits

     https://leetcode.com/problems/merge-two-sorted-lists/ https://www.youtube.com/watch?v=XIdigk956u0

  3. Linked List Cycle

     https://leetcode.com/problems/linked-list-cycle/ https://www.youtube.com/watch?v=gBTe7lFR3vc

  4. Reverse Linked List - Iterative AND Recursive

  video: https://www.youtube.com/watch?v=G0_I-ZF0S38&list=PLot-Xpze53lfQmTEztbgdp8ALEoydvnRQ&index=10&pp=iAQB code: https://leetcode.com/problems/reverse-linked-list/

  5. Palindrome Linked List

     video: https://www.youtube.com/watch?v=yOzXms1J6Nk&list=PLot-Xpze53lfQmTEztbgdp8ALEoydvnRQ&index=13 problem:

  6. Remove Linked List element:

     video: https://www.youtube.com/watch?v=JI71sxtHTng&list=PLot-Xpze53lfQmTEztbgdp8ALEoydvnRQ&index=21&pp=iAQB problem:

Week 3 --continue

 #Recursion
  1. Merge Two Sorted Lists
     Problem: https://leetcode.com/problems/merge-two-sorted-lists/
 Video: https://www.youtube.com/watch?v=XIdigk956u0

  2. Reverse linked Lists
     Problem: https://leetcode.com/problems/reverse-linked-list/
 Video: https://www.youtube.com/watch?v=G0_I-ZF0S38

  3. Power of two
     Problem: https://leetcode.com/problems/power-of-two/

  4. Power of three
     Problem: https://leetcode.com/problems/power-of-three/

  5. Power of four
     Problem: https://leetcode.com/problems/power-of-four/

  6. Swap nodes in pair
     Problem: https://leetcode.com/problems/swap-nodes-in-pairs/
 Video: https://www.youtube.com/watch?v=o811TZLAWOo

  7. Pow(x, n)
     Problem: https://leetcode.com/problems/powx-n/
 Video: https://www.youtube.com/watch?v=g9YQyYi4IQQ&t=628s

  8. Reorder List
     Problem: https://leetcode.com/problems/reorder-list/
 Video: https://www.youtube.com/watch?v=xRYPjDMSUFw

  9. Remove Nodes From Linked List
     Problem: https://leetcode.com/problems/remove-nodes-from-linked-list/
 
  10. Add Two Numbers
     Problem: https://leetcode.com/problems/add-two-numbers/
 Video: https://www.youtube.com/watch?v=wgFPrzTjm7s&t=230s

Some good resources:

• Bit Manipulation Reading: https://www.youtube.com/watch?v=7jkIUgLC29I