The course is made for people who want to learn DSA from A to Z for FREE from one of India’s top educators in DSA.
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What is Strivers A2Z DSA Course/Sheet?
This course is made for people who want to learn DSA from A to Z for free in a wellorganized and structured manner. The lecture quality is better than what you get in paid courses, the only thing we don’t provide is doubt support, but trust me our YouTube video comments resolve that as well, we have a wonderful community of 250K+ people who engage in all of the videos.
There might be a lot of existing courses/sheets in the market, but this is better in terms of structure, and the number of questions we will be doing. We just don’t teach the basics, we cover all the varieties, and we go in super depth for each topic, so that you are well prepared for any of your interviews.
Disclaimer: If you know DSA, and you have limited time to prepare for interviews, we recommend you to do the crisp and handpicked Striver’s SDE Sheet, which is used by almost everyone who prepares for FAANG and other companies.
Why trust the course?
This is a course/sheet which is prepared by Raj Vikramaditya A.K.A Striver, Candidate Master, 6*, who currently works at Google Warsaw. He had offers from Facebook London, and prior to this, he worked at Media.net(Directi). He has also interned at Amazon India. His channel takeUforward is currently India’s No.1 channel in the DSA niche when you talk about views generated every month.
Testimonials?
We have had amazing reviews from people who work at Google, Amazon, Facebook, etc. You can check them on Striver’s Instagram or our Linkedin as well. So, what are you waiting for? Let’s start our journey to learn DSA today.
Note: If you find the course/sheet useful, you can also contribute an article or solution for any problem to be published on takeuforward.org! Click here for more details.
Step 1: Learn the basics
Step 1.1: Things to Know in C++/Java/Python or any language
Step 1.2: Buildup Logical Thinking
Do all these patterns
Step 1.3: Learn STL/JavaCollections or similar thing in your language
Topic/Article  Solution  

C++ STL  
Java Collections 
Step 1.4: Know Basic Maths
Topic/Article  GfG  Solution  Leetcode  

Count Digits  
Reverse a Number  
Check Palindrome  
GCD Or HCF  
Armstrong Numbers  
Print all Divisors  
Check for Prime 
Step 1.5: Learn Basic Recursion
Topic/Article  GfG  Solution  Leetcode  

Understand recursion by print something N times  
Print name N times using recursion  
Print 1 to N using recursion  
Print N to 1 using recursion  
Sum of first N numbers  
Factorial of N numbers  
Reverse an array  
Check if a string is palindrome or not  
Fibonacci Number 
Step 1.6: Learn Basic Hashing
Topic/Article  GfG  Solution  Leetcode  

Hashing Theory  
Counting frequencies of array elements  
Find the highest/lowest frequency element 
Step 2: Learn Important Sorting Techniques
Step 2.1: SortingI
Topic/Article  GfG  Video  Leetcode  

Selection Sort  
Bubble Sort  
Insertion Sort 
Step 2.2: SortingII
Topic/Article  GfG  Video  Leetcode  

Merge Sort  
Recursive Bubble Sort  
Recursive Insertion Sort  
Quick Sort 
Step 3: Solve Problems on Arrays [Easy > Medium > Hard]
Step 3.1: Easy
Topic/Article  GfG  Solution  Leetcode  

Largest Element in an Array  
Second Largest Element in an Array without sorting  
Check if the array is sorted  
Remove duplicates from Sorted array  
Left Rotate an array by one place  
Left rotate an array by D places  
Move Zeros to end  
Linear Search  
Find the Union and intersection of two sorted arrays  
Find missing number in an array  
Maximum Consecutive Ones  
Subarray with given sum  
Find the Missing Number  
Find the number that appears once, and other numbers twice.  
Search an element in a 2D matrix  
Find the row with maximum number of 1’s 
Step 3.2: Medium
Topic/Article  GfG  Solution  Leetcode  

2Sum Problem  
Sort an array of 0’s 1’s and 2’s  
Majority Element (>n/2 times)  
Kadane’s Algorithm, maximum subarray sum  
Print subarray with maximum subarray sum (extended version of above problem)  
Stock Buy and Sell  
Rearrange the array in alternating positive and negative items  
Next Permutation  
Leaders in an Array problem  
Longest Consecutive Sequence in an Array  
Set Matrix Zeros  
Rotate Matrix by 90 degrees  
Print the matrix in spiral manner 
Step 3.3: Hard
Step 4: Binary Search [1D, 2D Arrays, Search Space]
Step 4.1: Learning BS on 1D Arrays
Topic/Article  GfG  Solution  Leetcode  

Binary Search to find X in sorted array  
Implement Lower Bound  
Implement Upper Bound  
Search Insert Position  
Check if Input array is sorted  
Find the first or last occurrence of a given number in a sorted array  
Count occurrences of a number in a sorted array with duplicates  
Find peak element  
Search in Rotated Sorted Array I  
Search in Rotated Sorted Array II  
Find minimum in Rotated Sorted Array  
Single element in a Sorted Array  
Find kth element of two sorted arrays  
Find out how many times has an array been rotated 
Step 4.2: Applying BS on 2D Arrays
Topic/Article  GfG  Solution  Leetcode  

Search in a 2 D matrix  
Find Peak Element  
Matrix Median 
Step 4.3: Find Answers by BS in Search Space
Topic/Article  GfG  Solution  Leetcode  

Find square root of a number in log n  
Find the Nth root of a number using binary search  
Koko Eating Bananas  
Minimum days to make M bouquets  
Find the smallest Divisor  
Capacity to Ship Packages within D Days  
Median of two sorted arrays  
Aggressive Cows  
Book Allocation Problem  
Split array – Largest Sum  
Kth Missing Positive Number  
Minimize Max Distance to Gas Station  
Median of 2 sorted arrays  
Kth element of 2 sorted arrays 
Step 5: Strings [Basic and Medium]
 String has extremely hard problems for beginners in its hard section, so it is covered in the later half
 String has lesser problems, because most of the string problems have hard concepts like DP or others which are covered in different topics.
Step 5.1: Basic and Easy String Problems
Topic/Article  GfG  Solution  Leetcode  

Remove outermost Paranthesis  
Reverse words in a given string / Palindrome Check  
Largest odd number in a string  
Longest Common Prefix  
Isomorphic String  
check whether one string is a rotation of another  
Check if two strings are anagram of each other 
Step 5.2: Medium String Problems
Step 6: Learn LinkedList [Single/Double LL, Medium, Hard]
Step 6.1: Learn 1D LinkedList
Topic/Article  GfG  Solution  Leetcode  

Introduction to LinkedList, learn about struct, and how is node represented  
Inserting a node in LinkedList  
Deleting a node in LinkedList  
Find the length of the linkedlist [learn traversal]  
Search an element in the LL 
Step 6.2: Learn Doubly LinkedList
Topic/Article  GfG  Solution  Leetcode  

Introduction to DLL, learn about struct, and how is node represented  
Insert a node in DLL  
Delete a node in DLL  
Reverse a DLL 
Step 6.3: Medium Problems of LL
Topic/Article  GfG  Solution  Leetcode  

Middle of a LinkedList [TortoiseHare Method]  
Reverse a LinkedList [Iterative]  
Reverse a LL [Recursive]  
Detect a loop in LL  
Find the starting point in LL  
Length of Loop in LL  
Check if LL is palindrome or not  
Segrregate odd and even nodes in LL  
Remove Nth node from the back of the LL  
Delete the middle node of LL  
Sort LL  
Sort a LL of 0’s 1’s and 2’s by changing links  
Find the intersection point of Y LL  
Add 1 to a number represented by LL  
Add 2 numbers in LL 
Step 6.4: Medium Problems of DLL
Topic/Article  GfG  Solution  Leetcode  

Delete all occurrences of a key in DLL  
Find pairs with given sum in DLL  
Remove duplicates from sorted DLL 
Step 6.5: Hard Problems of LL
Topic/Article  GfG  Solution  Leetcode  

Reverse LL in group of given size K  
Rotate a LL  
Flattening of LL  
Clone a Linked List with random and next pointer 
Step 7: Recursion [PatternWise]
 Please complete the basic recursion questions in Step 1
 To learn completely recursion, watch this playlist > Link
Step 7.1: Get a Strong Hold
Topic/Article  GfG  Solution  Leetcode  

Recursive Implementation of atoi()  
Pow(x, n)  
Count Good numbers  
Sort a stack using recursion  
Reverse a stack using recursion 
Step 7.2: Subsequences Pattern
Topic/Article  GfG  Solution  Leetcode  

Generate all binary strings  
Generate Paranthesis  
Print all subsequences/Power Set  
Learn All Patterns of Subsequences (Theory)  
Count all subsequences with sum K  
Check if there exists a subsequence with sum K  
Combination Sum  
Combination SumII  
Subset SumI  
Subset SumII  
Combination Sum – III  
Letter Combinations of a Phone number 
Step 7.3: Trying out all Combos / Hard
Topic/Article  GfG  Solution  Leetcode  

Palindrome Partitioning  
Word Search  
N Queen  
Rat in a Maze  
Word Break  
M Coloring Problem  
Sudoko Solver  
Expression Add Operators 
Step 8: Bit Manipulation [Concepts & Problems] & Advanced Maths
 It is one of the smallest topics in DSA, learn the basic concepts.
 There are only few problems which are repeatedly asked in Interviews which have been added.
Step 8.1: Learn Bit Manipulation
Step 9: Stack and Queues [PreInPostfix, Monotonic Stack]
Step 9.1: Learning
Step 9.2: Prefix, Infix, PostFix Conversion Problems
Topic/Article  GfG  Solution  Leetcode  

Infix to Postfix Conversion using Stack  
Prefix to Infix Conversion  
Prefix to Postfix Conversion  
Postfix to Prefix Conversion  
Postfix to Infix  
Convert Infix To Prefix Notation 
Step 9.3: Monotonic Stack/Queue Problems [VVV. Imp]
Topic/Article  GfG  Solution  Leetcode  

Next Greater Element  
Next Greater Element 2  
Next Smaller Element  
Number of NGEs to the right  
Trapping Rainwater  
Sum of subarray minimum  
Stock span problem  
Asteroid Collision  
Sum of subarray ranges  
Remove k Digits  
Largest rectangle in a histogram  
Maximal Rectangles 
Step 9.4: Implementation Problems
Topic/Article  GfG  Solution  Leetcode  

Sliding Window maximum  
Stock Span Problem  
The Celebrity Problem  
Rotten Oranges  
LRU cache (IMPORTANT)  
LFU cache 
Step 10: Sliding Window & Two Pointer Combined Problems
Step 10.1: Medium Problems
Topic/Article  GfG  Solution  Leetcode  

Longest Substring Without Repeating Characters  
Max Consecutive Ones III  
Fruit Into Baskets  
longest repeating character replacement  
Binary subarray with sum  
Count number of nice subarrays  
Number of substring containing all three characters  
Maximum point you can obtain from cards 
Step 10.2: Hard Problems
Topic/Article  GfG  Solution  Leetcode  

Longest Substring with At Most K Distinct Characters  
Subarray with k different integers  
Minimum Window Substring  
Minimum Window Subsequence  Problem 2 
Step 11: Heaps [Learning, Medium, Hard Problems]
Step 11.1: Learning
Topic/Article  GfG  Solution  Leetcode  

Introduction to Priority Queues using Binary Heaps  
Min Heap and Max Heap Implementation  
Check if an array represents a minheap or not  
Convert min Heap to max Heap 
Step 11.2: Medium Problems
Topic/Article  GfG  Solution  Leetcode  

Kth largest element in an array [use priority queue]  
Kth smallest element in an array [use priority queue]  
Sort K sorted array  
Merge M sorted Lists  
Replace each array element by its corresponding rank  
Task Scheduler  
Hands of Straights 
Step 12: Greedy Algorithms [Easy, Medium/Hard]
Step 12.1: Easy Problems
Topic/Article  GfG  Solution  Leetcode  

Assign Cookies  
Fractional Knapsack Problem  
Greedy algorithm to find minimum number of coins  
Lemonade Change  
Valid Paranthesis Checker 
Step 12.2: Medium/Hard
Topic/Article  GfG  Solution  Leetcode  

N meetings in one room  
Jump Game  
Jump Game 2  
Minimum number of platforms required for a railway  
Job sequencing Problem  
Candy  
Program for Shortest Job First (or SJF) CPU Scheduling  
Program for Least Recently Used (LRU) Page Replacement Algorithm  
Insert Interval  
Merge Intervals  
Nonoverlapping Intervals 
Step 13: Binary Trees [Traversals, Medium and Hard Problems]
 An entire playlist is made on it, it is more than enough
Step 13.1: Traversals
Topic/Article  GfG  Solution  Leetcode  

Introduction to Trees  
Binary Tree Representation in C++  
Binary Tree Representation in Java  
Binary Tree Traversals in Binary Tree  
Preorder Traversal of Binary Tree  
Inorder Traversal of Binary Tree  
Postorder Traversal of Binary Tree  
Level order Traversal / Level order traversal in spiral form  
Iterative Preorder Traversal of Binary Tree  
Iterative Inorder Traversal of Binary Tree  
Postorder Traversal of Binary Tree using 2 stack  
Postorder Traversal of Binary Tree using 1 stack  
Preorder, Inorder, and Postorder Traversal in one Traversal 

Step 13.2: Medium Problems
Step 13.1: Hard Problems
Topic/Article  GfG  Solution  Leetcode  

Root to Node Path in Binary Tree  
LCA in Binary Tree  
Maximum width of a Binary Tree  
Check for Children Sum Property  
Print all the Nodes at a distance of K in a Binary Tree  
Minimum time taken to BURN the Binary Tree from a Node  
Count total Nodes in a COMPLETE Binary Tree  
Requirements needed to construct a Unique Binary Tree  Theory  Link  
Construct Binary Tree from inorder and preorder  
Construct the Binary Tree from Postorder and Inorder Traversal  
Serialize and deserialize Binary Tree  
Morris Preorder Traversal of a Binary Tree  
Morris Inorder Traversal of a Binary Tree  
Flatten Binary Tree to LinkedList 
Step 14: Binary Search Trees [Concept and Problems]
 An entire playlist is made on it, it is more than enough
Step 14.1: Concepts
Topic/Article  GfG  Solution  Leetcode  

Introduction to Binary Search Tree  
Search in a Binary Search Tree  
Find Min/Max in BST 
Step 14.2: Practice Problems
Topic/Article  GfG  Solution  Leetcode  

Ceil in a Binary Search Tree  
Floor in a Binary Search Tree  
Insert a given Node in Binary Search Tree  
Delete a Node in Binary Search Tree  
Find Kth smallest/largest element in BST  
Check if a tree is a BST or BT  
LCA in Binary Search Tree  
Construct a BST from a preorder traversal  
Inorder Successor/Predecessor in BST  
Merge 2 BST’s  
Two Sum In BST  Check if there exists a pair with Sum K  
Recover BST  Correct BST with two nodes swapped  
Largest BST in Binary Tree 
Step 15: Graphs [Concepts & Problems]
 The new Graph playlist is under progress, you can check here > Link
 In case you have lesser time, you can check the old graph series here > Link
Step 15.1: Learning
Topic/Article  GfG  Solution  Leetcode  

Graph and Types  
Graph Representation  C++  
Graph Representation  Java  
Connected Components  Logic Explanation  
BFS  
DFS 
Step 15.2: Problems on BFS/DFS
Topic/Article  GfG  Solution  Leetcode  

Number of provinces (leetcode)  
Connected Components Problem in Matrix  
Rotten Oranges  
Flood fill  
Cycle Detection in unirected Graph (bfs)  
Cycle Detection in undirected Graph (dfs)  
0/1 Matrix (Bfs Problem)  
Surrounded Regions (dfs)  
Number of Enclaves [flood fill implementation – multisource]  
Word ladder – 1  
Word ladder – 2  
Number of Distinct Islands [dfs multisource]  
Bipartite Graph (DFS)  
Cycle Detection in Directed Graph (DFS) 
Step 15.3: Topo Sort and Problems
Topic/Article  GfG  Solution  Leetcode  

Topo Sort  
Kahn’s Algorithm  
Cycle Detection in Directed Graph (BFS)  
Course Schedule – I  
Course Schedule – II  
Find eventual safe states  
Alien dictionary 
Step 15.4: Shortest Path Algorithms and Problems
Step 15.5: MinimumSpanningTree/Disjoint Set and Problems
Topic/Article  GfG  Solution  Leetcode  

Minimum Spanning Tree  
Prim’s Algorithm  
Disjoint Set [Union by Rank]  
Disjoint Set [Union by Size]  
Kruskal’s Algorithm  
Number of operations to make network connected  
Most stones removed with same rows or columns  
Accounts merge  
Number of island II  
Making a Large Island  
Swim in rising water  [HARD] 
Step 15.6: Other Algorithms
Topic/Article  GfG  Solution  Leetcode  

Bridges in Graph  
Articulation Point  
Kosaraju’s Algorithm 
Step 16: Dynamic Programming [Patterns and Problems]
 An entire playlist is made on it, it is more than enough
Step 16.1: Introduction to DP
Topic/Article  GfG  Solution  Leetcode  

Dynamic Programming Introduction 
Step 16.2: 1D DP
Topic/Article  GfG  Solution  Leetcode  

Climbing Stars  
Frog Jump(DP3)  
Frog Jump with k distances(DP4)  
Maximum sum of nonadjacent elements (DP 5)  
House Robber (DP 6) 
Step 16.3: 2D/3D DP and DP on Grids
Step 16.4: DP on Subsequences
Step 16.5: DP on Strings
Step 16.6: DP on Stocks
Step 16.7: DP on LIS
Step 16.8: MCM DP  Partition DP
Step 16.9: DP on Squares
Topic/Article  GfG  Solution  Leetcode  

Maximum Rectangle Area with all 1’s(DP55)  
Count Square Submatrices with All Ones(DP56) 
Step 17: Tries [Concepts and Problems]
 Trie has limited problems, and usually they ask directly.
 An entire playlist is made on it, you don’t need anything out of what is given below.
Step 17.1: Theory
Topic/Article  GfG  Solution  Leetcode  

Implement TRIE  INSERT  SEARCH  STARTSWITH 
Step 17.2: Problems
Topic/Article  GfG  Solution  Leetcode  

Implement Trie – 2 (Prefix Tree)  
Longest String with All Prefixes  
Number of Distinct Substrings in a String  
Bit PreRequisites for TRIE Problems  
Maximum XOR of two numbers in an array  
Maximum XOR With an Element From Array 
Step 18: Strings [Hard Problems and Standard Algos]
 Basic, Medium, and other concepts on Strings have been covered above.
 In this we cover the algorithms, and applications which are generally asked, it is slightly tough to understand intuition wise, so don’t be much concerned.
Step 18.1: Hard Problems
Step 19: Request from Striver
If this Course/Sheet helped you in any possible way, you can always help me by doing any of the followings. It won’t cost you anything, eveything is free, but yes, I will be able to reach more and more people by word of mouth.
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 You can share it on Whatsapp as well, by clicking here.
 When you start the Course/Sheet you can comment on the launch video, and when you end, you can comment your end date, experience, mistakes, so that the juniors of the next generation don’t repeat them 🙂
 If you are willing to pay or donate any money, feel free to donate to any of the nearby organisations, I will be super happy. We don’t need money as of now. By God’s grace we are happy and doing well.
Hurrah!! You are ready for your placement after some months of hard work! All the best, keep striving…
Striver
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