Lead Product Engineer Interview Questions and Answers

A hash map is a data structure that stores key-value pairs and uses a hash function to map keys to their corresponding values.

• Hash map works by using a hash function to determine the index of the key-value pair in an array.

• Complexity for putting data is O(1) on average, but can be O(n) in worst case scenarios.

• Complexity for getting data is also O(1) on average, but can be O(n) in worst case scenarios.

• Hash maps are commonly used in programming for fast lookups and data storage...read more

Use a hashmap to store elements and their corresponding complements to find pairs with given sum in list of integers.

• Iterate through the list of integers and store each element in a hashmap.

• For each element, check if its complement (target - element) exists in the hashmap.

• If the complement exists, add the pair to the result array.

LinkedHashMap is a data structure that combines features of a linked list and a hash map.

• Combines features of linked list and hash map

• Maintains insertion order

• Allows null keys and values

• Access order can be maintained using constructor parameter