Wissen interview questions
Online test → Technical → Technical → HR·100% entry level
CS fundamentals
Showing 31 of 90 reported in this area
Explain OOP concepts such as inheritance, association, aggregation, composition, and polymorphism with examples
Write an SQL coding query
What is pure abstraction in Java?
What is the diamond problem in Java?
Explain Java Collections and synchronization.
What are database indexes and why are they used?
Answer theoretical questions on DBMS, OOP, and SQL.
Determine the normal form of a given database table
Explain multithreading and synchronization in Java.
What is serialization? Explain its internal working.
Write a medium-level SQL query using JOIN operations
Explain pointers including referencing and addressing
Explain the different types of database normalization.
What are B-tree and B+ tree? Explain their differences.
Explain the difference between Merge Sort and Quick Sort
Write SQL queries to join tables based on the designed ER model
Write a C++ struct for a generic linked list using void pointers.
Write a SQL query using JOIN operations to retrieve required data
Explain internal working of HashMap, ConcurrentHashMap, and TreeMap.
Explain the difference between wait() and sleep() in Java threading.
Explain processes, threads, semaphores, mutexes, deadlock, and starvation.
Explain operating system concepts including processes, threads, and caching
Improve the robustness of the tree construction code to handle extreme cases.
Design a database schema for an eCommerce system and write required SQL queries
Exceptions hierarchy in Java and rules for overridden methods throwing exceptions.
SQL: Find names of students enrolled in more than 3 courses using subquery and join.
Difference between abstract class and interface. Explain default methods in interfaces.
Explain Operating System concepts including processes, threads, caching, and page faults
Explain your approach to the written coding solutions and discuss possible optimizations.
List the data structures used in constructing a page table with an LRU swapping algorithm.
Given matrices of sizes 2x2, 2x3, and 3x3, how would you store them in a single database table?
DSA
Showing 23 of 81 reported in this area
Detect a loop in a linked list
Find the height of a binary tree
Binary Search related problem
Print the right view of a binary tree.
Medium-level string manipulation problem
Find the top view of a given binary tree.
Print all root-to-leaf paths of a binary tree.
Find the top 10 maximum elements from an array.
What is a stack? Implement a queue using stacks.
Check whether a binary tree is a binary search tree.
Solve coding questions involving array manipulation.
Print the zig-zag (spiral) order traversal of a binary tree.
Find the nearest smaller element on the left for each array element.
Given a list of strings, group all anagrams together into a 2D array.
Design a stack that supports retrieving the minimum element in O(1) time.
Delete a node from a linked list given only reference to that node in O(1).
Find the most frequently occurring palindromic words of length 4 in a given text.
Check whether a given number is a perfect cube without using math library functions.
Print a linked list in reverse order without modifying the linked list in O(n) time.
Construct a binary tree given its inorder and postorder traversals (write runnable code).
Given a multi-paragraph text, find the most frequently occurring words across the entire text.
Solve another query-based array problem requiring efficient handling of queries on array data.
Find a subarray whose sum adds up to a given value when the array may contain negative integers.
System design
4 questions reported in this area
Design a pattern lock system.
Design a system to find the largest N files and folders from a directory structure.
How would you train a machine learning model to detect outliers in bank transactions?
Design an ER model for a shopping site or app, including tables, primary keys, and foreign keys
Behavioural
1 questions reported in this area
Discuss the topic: 'The future of Nuclear Power'.
Puzzles
1 questions reported in this area
How to measure 45 minutes using two identical wires
Showing 60 of 149 questions. Ranked by how often the same question came back across reports.
Practise a Wissen-style interview
A spoken interview built from these questions, scored when you finish; the report is yours.
Start practisingCommon questions
What questions does Wissen ask?
Candidate interview reports most often cover CS fundamentals (50%) and DSA (45%).
How many rounds does Wissen interview have?
Candidate interview reports show an average of 4.1 rounds per experience, with a typical sequence of Online test → Technical → Technical → HR. Individual interview paths can vary.
Is the Wissen interview hard?
Among questions with a reported difficulty, the mix is easy 43%, medium 51%, hard 6%.