SDE SHEET A Complete Guide for SDE Preparation (original) (raw)
Last Updated : 22 Sep, 2025
Here is a curated list of the most popular questions among important topics, such as Programming Languages, Data Structure and Algorithms (DSA), CS Subjects, Aptitude, etc, asked in the Software Development Engineer Interviews.
- This sheet contains a wide range of coding questions from different Data Structures and Algorithms.
- It covers all the segments round-wise like MCQs, DSA (Coding Questions), CS Subjects, Puzzles, System Design, Projects.
- It is helpful for both **Students and Experienced.
Try our free course **GfG 160 where we have 160 most asked problems along with well written editorials and video explanations. The course also has 90 bonus problems.
**Data Structures and Algorithms (250)
Below are the list of top problems topic wise:
Arrays (21)
Sorting (13)
Important Sorting Algorithms: Bubble Sort, Selection Sort, Insertion Sort, Merge Sort, Quick Sort, Cycle Sort, Counting Sort, Bucket Sort, Heap Sort, Radix Sort
Strings (14)
| First Repeated Character | Easy |
|---|---|
| Reverse Words | Easy |
| Roman Number to Integer | Easy |
| Check Anagram | Easy |
| Remove Duplicates | Easy |
| Longest Substring Without Repeating Characters | Medium |
| Rabin-Karp Algorithm | Medium |
| Z algorithm | Medium |
| Longest Palindromic Substring | Medium |
| Look-and-Say Sequence | Medium |
| Number to English Words | Medium |
| KMP Algorithm | Hard |
| Minimum Characters to Add at Front for Palindrome | Hard |
| Smallest Window Containing All Characters of Another String | Hard |
Hashing (15)
Binary Search (10)
Matrix (6)
Recursion and Backtracking (13)
| Find all Unique Subsets | Medium |
|---|---|
| Generate Sums of all Subsets | Medium |
| Tower of Hanoi | Medium |
| Generate all Unique Permutations | Medium |
| Rat in a Maze | Medium |
| Combination Sum (Repeated Selection) | Medium |
| Combination Sum II (Single Selection) | Medium |
| Generate all Palindromic Partitions | Medium |
| Generate Valid IP Addresses | Medium |
| Word Search | Medium |
| N-Queen Problem | Hard |
| Solve Sudoku | Hard |
| Word Break | Hard |
Stack (10)
Queue (3)
| Moving Average from Data Stream | Easy |
|---|---|
| Design Circular Queue | Medium |
| Stream First Non-repeating | Medium |
Deque (3)
| Maximum of all subarrays of size K | Medium |
|---|---|
| Longest Subarray with Absolute Difference Less than or Equal to K | Medium |
| Shortest Subarray with Sum at Least K | Hard |
Stack + Queue (2)
| Stack using Queues | Easy |
|---|---|
| Queue using Stacks | Easy |
Heap (10)
| Connect Ropes with Minimum Cost | Easy |
|---|---|
| Implement Binary Heap | Medium |
| Rearrange String to Avoid Adjacent Duplicates | Medium |
| Kth Largest Element | Medium |
| Merge k Sorted Arrays | Medium |
| Top K Frequent Elements | Medium |
| Merge K Sorted Linked Lists | Medium |
| Kth Smallest Element in Matrix | Medium |
| Sort a K Sorted Array | Medium |
| Find Median in Stream | Hard |
Bit Manipulation (12)
Important Bit operations: Set, Clear and Toggle a Bit, Strip Last Set Bit, Count Set Bits
| K-th Bit is Set or Not | Easy |
|---|---|
| Swap 2 Numbers using XOR | Easy |
| Check if a Number is a Power of 2 | Easy |
| Rightmost Set Bit | Easy |
| Rightmost Different Bit | Easy |
| Toggle Bits in Given Range | Easy |
| Single in Couples | Easy |
| Division without *, /, or % | Medium |
| Count Set Bits from 1 to N | Medium |
| Generate Subsets using Bit Manipulation | Medium |
| Find Two Numbers with Odd Occurrences | Medium |
| Maximum Subset XOR | Hard |
Linked List (16)
Binary Tree (19)
Important Traversal: Inorder, Preorder, Postorder, Level Order
| Level Order Traversal in Spiral Form | Easy |
|---|---|
| Height of Binary Tree | Easy |
| Balanced Tree Check | Easy |
| Check Symmetric Tree | Easy |
| Check Identical Trees | Easy |
| Left View of Binary Tree | Easy |
| Top View of Binary Tree | Medium |
| Bottom View of Binary Tree | Medium |
| Diagonal Tree Traversal | Medium |
| Vertical Tree Traversal | Medium |
| LCA in Binary Tree | Medium |
| Tree Boundary Traversal | Medium |
| Diameter of a Binary Tree | Medium |
| Connect Nodes of Levels | Medium |
| Serialize and Deserialize a Binary Tree | Medium |
| Construct Tree from Inorder & Preorder | Medium |
| Maximum Path Sum between 2 Nodes | Medium |
| Max Path Sum between 2 Leaf Nodes | Hard |
| Convert Binary Tree to Doubly Linked List | Hard |
Binary Search Tree (12)
| Check for BST | Easy |
|---|---|
| LCA in BST | Easy |
| Sorted Array to BST | Easy |
| Kth Largest Element in BST | Easy |
| Ceil in BST | Medium |
| Largest BST | Medium |
| Merge two BST 's | Medium |
| Preorder to BST | Medium |
| Predecessor and Successor in BST | Medium |
| Binary Search Tree Iterator | Medium |
| Delete a Node from BST | Medium |
| Balance a Binary Search Tree | Medium |
Greedy (9)
| Minimize the Sum of Product | Easy |
|---|---|
| Largest Number Possible | Easy |
| Minimum Number of Coins | Easy |
| Assign Cookies | Easy |
| Gas Station | Medium |
| Activity Selection | Medium |
| Fractional Knapsack | Medium |
| Job Sequencing | Medium |
| Huffman Encoding | Hard |
Dynamic Programming (21)
| Ways to Reach the Nth Stair | Medium |
|---|---|
| House Robber II | Medium |
| Coin Change (Minimum Coins) | Medium |
| Coin Change (Count Ways) | Medium |
| Longest Common Substring | Medium |
| Longest Increasing Subsequence | Medium |
| Longest Common Subsequence | Medium |
| 0 - 1 Knapsack Problem | Medium |
| Partition Equal Subset Sum | Medium |
| Minimum Insertions to Form Palindrome | Medium |
| Maximize The Cut Segments | Medium |
| Maximum Path Sum in Matrix | Medium |
| Rod Cutting | Medium |
| Egg Dropping Puzzle | Medium |
| Word Break | Medium |
| Optimal Strategy For A Game | Medium |
| Wildcard Pattern Matching | Medium |
| Edit Distance | Medium |
| Matrix Chain Multiplication | Hard |
| Palindromic Partitioning | Hard |
| Boolean Parenthesization | Hard |
Graph (32)
| DFS of Graph | Easy |
|---|---|
| BFS of Graph | Easy |
| Detect Cycle in Undirected Graph | Medium |
| Detect Cycle in a Directed Graph | Medium |
| Detect a Negative Cycle | Medium |
| Topological Sorting | Medium |
| Shortest Path in Directed Acyclic Graph | Medium |
| Kahn’s Algorithm | Medium |
| Dijkstra Algorithm | Medium |
| Bellman-Ford Algorithm | Medium |
| Floyd Warshall Algorithm | Medium |
| Prim’s Algorithm | Medium |
| Kruskal’s Algorithm | Medium |
| Euler Path and Circuit | Medium |
| Hamiltonian Path and Circuit | Medium |
| Kosaraju’s Algorithm | Hard |
| Tarjan’s Algorithm | Hard |
| Bridges in Graph | Hard |
| Articulation Points in Graph | Hard |
| Disjoint Set (Union Find Algorithm) | Hard |
| Mother Vertex | Medium |
| Rotten Oranges | Medium |
| Flood fill Algorithm | Medium |
| Replace O's with X's | Medium |
| Steps by Knight | Medium |
| Bipartite Graph | Medium |
| Number of Islands | Medium |
| Clone an Undirected Graph | Medium |
| M-Coloring Problem | Medium |
| Alien Dictionary | Hard |
| Circle of Strings | Hard |
| Minimum Cost Path | Hard |
Trie (6)
| Insert, Search and Delete in Trie | Medium |
|---|---|
| Longest Common Prefix of Strings | Medium |
| Prefix Suffix String | Medium |
| Word Break (Trie) | Hard |
| Phone Directory | Hard |
| Maximum XOR Subarray | Hard |
Computer Science Subjects
**1. Operating System
An operating system acts as an intermediary between the user of a computer and computer hardware. The purpose of an operating system is to provide an environment in which a user can execute programs conveniently and efficiently. Below links contains complete Operating System Study Material:
- Commonly Asked Operating Systems Interview Questions
- Last Minute Notes (LMNs) | Operating Systems
- Complete Tutorial on Operating System
**2. DBMS
Database is a collection of inter-related data which helps in efficient retrieval, insertion and deletion of data from database and organizes the data in the form of tables, Links, schemas, reports etc. Below Links contains complete DBMS study Material:
- Commonly Asked DBMS Interview Questions
- Commonly Asked DBMS Interview Questions | Set-2
- Last Minute Notes (LMNs) | DBMS
- Complete Tutorial on DBMS
**3. SQL
SQL stands for Structured Query Language. It is a language used to interact with the database, i.e to create a database, to create a table in the database, to retrieve data or update a table in the database. Below Links contains complete SQL study Material:
- SQL Interview Questions
- SQL Interview Questions | Set-2
- SQL Interview Questions | Set-3
- Complete Tutorial on SQL
**4. Computer Networks
A computer network is a system that connects numerous independent computers in order to share information (data) and resources. The integration of computers and other different devices allows users to communicate more easily. Below Links contains complete Computer Networks study Material:
- Commonly Asked Computer Networks Interview Questions
- Last Minute Notes (LMNs) | Computer Networks
- Complete Tutorial on Computer Networks
**Puzzles
Puzzles are one of the ways to check your problem-solving skills. These are tricky questions that let you think logically.
Try to solve the 20 most popular puzzles asked in Interviews
**Projects
Thoroughly revise all the work you have done till now in your projects. The grilling about projects can sometimes be very deep. Also, choose your words before you speak. Mention only those topics where you think you are fine to be grilled upon.
If you haven't made a project then take an idea from GfG Projects and start working on these.
**System Design
System Design is the process of designing the architecture, components, and interfaces for a system so that it meets the end-user requirements. System Design for tech interviews is something that can’t be ignored especially for experienced people Almost every IT giant whether it be Facebook, Amazon, Google, or any other ask various questions based on System Design concepts such as scalability, load-balancing, caching, etc. in the interview.
Please refer System Design tutorial that will help you to learn and master System Design concepts in the most efficient way from basics to advanced level.
**Bonus SDE Sheets
You can prepare for several types of interviews here. For instance, if you want to prepare for a Google interview, we have an SDE sheet specifically designed for that purpose. Here we attached the links to the top 5 product based and top 5 Service based preparation SDE Sheets.
| Product Based Company SDE Sheets | Service Based Company SDE Sheets |
|---|---|
| Facebook(Meta) SDE Sheet | Wipro SDE Sheet |
| Amazon SDE Sheet | Infosys SDE Sheet |
| Apple SDE Sheet | TCS SDE Sheet |
| Netflix SDE Sheet | Cognizant SDE Sheet |
| Google SDE Sheet | HCL SDE Sheet |