Top 50 Coding Questions for Placement Preparation
Introduction
Preparing for campus placements can feel overwhelming—especially when it comes to coding interviews. Every recruiter wants to test your problem-solving skills, coding logic, and data structure knowledge. The truth is, most companies ask a common set of coding problems that you can easily prepare in advance.
In this guide, we’ll cover the Top 50 Coding Questions for Placement Preparation, categorized into topics like arrays, strings, linked lists, dynamic programming, and more. By practicing these, you’ll not only improve your problem-solving ability but also gain confidence in handling interviews from companies like TCS, Infosys, Wipro, Cognizant, Accenture, and even top product-based firms like Amazon, Microsoft, and Google.
Why Coding Practice is Crucial for Placements
- Most IT recruiters shortlist candidates based on coding test performance.
- Practicing standard questions improves speed, accuracy, and logic-building skills.
- Interviewers often check how efficiently you can solve real-world problems using code.
- Many companies repeat coding questions with slight variations.
So, if you’re serious about landing your dream job, start with these 50 must-solve coding questions.
Top 50 Coding Questions for Placement Preparation
We’ve divided the questions topic-wise to make your preparation structured and easier.
1. Array Coding Questions
Arrays are the backbone of coding interviews. Questions here test your logic and ability to optimize solutions.
- Find the largest element in an array.
- Find the second largest element in an array.
- Reverse an array in place.
- Check if an array is sorted.
- Find the frequency of each element in an array.
- Move all negative elements to one side of the array.
- Find the missing number in a series (1 to n).
- Find the maximum subarray sum (Kadane’s Algorithm).
- Find the intersection of two arrays.
- Rotate an array by k positions.
2. String Coding Questions
String manipulation questions test your logical and analytical thinking.
- Reverse a string without using extra space.
- Check if a string is a palindrome.
- Find the longest palindrome substring.
- Count vowels and consonants in a string.
- Find the first non-repeating character.
- Remove all duplicate characters from a string.
- Check if two strings are anagrams.
- Find all permutations of a string.
- Implement strstr() function (substring search).
- Convert a Roman numeral to an integer.
3. Linked List Coding Questions
Linked lists are a favorite for placements as they test understanding of pointers and memory management.
- Reverse a linked list.
- Detect a cycle in a linked list.
- Find the middle element of a linked list.
- Merge two sorted linked lists.
- Remove duplicates from a linked list.
- Check if a linked list is a palindrome.
- Delete the nth node from the end.
- Find the intersection point of two linked lists.
- Flatten a linked list.
- Clone a linked list with random pointers.
4. Stack and Queue Questions
Stacks and queues are widely used in solving interview problems.
- Implement a stack using arrays.
- Implement a queue using stacks.
- Evaluate a postfix expression.
- Implement the next greater element problem.
- Design a circular queue.
5. Searching and Sorting Questions
Recruiters want to see if you can optimize solutions.
- Implement binary search.
- Implement merge sort.
- Implement quick sort.
- Find the kth largest element in an array.
- Count the number of inversions in an array.
6. Dynamic Programming (DP) Questions
Dynamic programming is crucial for product-based company interviews.
- Find the nth Fibonacci number using DP.
- Find the longest common subsequence (LCS).
- Find the longest increasing subsequence (LIS).
- Solve the 0/1 Knapsack problem.
- Find the minimum number of coins for a given value.
7. Tree and Graph Questions
Companies often test your understanding of advanced data structures.
- Find the height of a binary tree.
- Perform inorder, preorder, and postorder traversals.
- Level order traversal of a tree.
- Detect a cycle in a graph using BFS/DFS.
- Implement Dijkstra’s algorithm for shortest path.
How to Approach These Coding Questions
- Start with basics (arrays, strings) before moving to advanced topics.
- Solve each problem in both brute-force and optimized approaches.
- Practice on platforms like LeetCode, GeeksforGeeks, and HackerRank.
- Write clean, modular code with comments.
- Time yourself to simulate real test conditions.
Additional Tips for Placement Preparation
- Focus on time complexity and space complexity.
- Revise important concepts like recursion, hashing, and pointers.
- Take mock tests to get exam-like practice.
- Don’t just memorize — understand the logic behind each problem.
FAQ Section
Q1. How many coding questions should I practice before placements?
You should aim to practice at least 150–200 coding problems across arrays, strings, linked lists, trees, DP, and graphs.
Q2. Are these 50 coding questions enough for service-based company placements?
Yes, for companies like TCS, Wipro, Cognizant, and Infosys, these 50 questions cover the majority of asked topics.
Q3. How can I improve problem-solving speed in coding tests?
Time yourself while practicing, focus on optimizing solutions, and revise frequently asked problems.
Q4. Which programming language should I use for placements?
C++, Java, and Python are most preferred. Choose the one you’re most comfortable with.
Q5. Do product-based companies like Amazon and Google ask these questions?
Yes, but with more complexity. They may ask variations of these problems with added constraints.
Conclusion
Preparing for placements doesn’t have to be stressful. By systematically solving these Top 50 Coding Questions, you’ll cover almost all the important areas interviewers focus on. The key is consistent practice and focusing on logic rather than memorization.
Start today, build confidence, and ace your coding interviews.
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