Top 20 Hashing Technique based Interview Questions

Hashing is a powerful technique in Data Structures and Algorithms (DSA) that involves mapping data to a fixed-size value using a hash function. The key advantage of hashing is its ability to provide fast lookups, often achieving constant time complexity, O(1), for operations like searching and inserting elements. However, a good hash function is essential to minimize collisions, where multiple inputs produce the same hash value.

Easy Problems

• Subset Check
• Union and Intersection of two Linked Lists
• A pair with given sum
• Two pair sum
• Largest subarray with 0 sum
• Distinct elements in K-size Window
• Palindrome Substring Queries
• Missing elements of a range
• All subarrays with 0 sum
• Symmetric Pairs
• Duplicates within k distance

Medium and Hard Problems

• Find Itinerary from a given list of tickets
• Largest subarray with equal number of 0s and 1s
• Count Subarrays with XOR
• Longest Consecutive Subsequence
• Pair Sum Divisible by K
• Smallest Range from K Lists
• Internal Working of HashMap in Java
• Separate Chaining for Collision Handling
• Hash Table with Chaining in Java
• Open Addressing for Collision Handling

Related Links

• Articles on Hashing
• Practice Problems on Hashing