KPMG India Interview Questions and Answers

Hashing is a technique to map data to a fixed-size table. Time complexity of searching a hash table is O(n) in worst case.

• Hashing is used to store and retrieve data quickly

• It uses a hash function to map data to a fixed-size table

• In the best case, searching a hash table takes O(1) time

• In the worst case, all the data maps to the same index and searching takes O(n) time

• Collision resolution techniques like chaining and open addressing are used to handle collisions

An array of key-value pairs is the best data structure for a dictionary.

• Use a hash table or a balanced tree to implement the dictionary.

• Keys should be unique and immutable.

• Values can be any data type.

• Access time should be O(1) or O(log n) depending on the implementation.

• Examples: Python's dict, Java's HashMap, C++'s unordered_map.

Add mathematical operators to make given expressions true.

• Use addition, subtraction, multiplication, division, exponentiation, and parentheses to modify the expressions.

• For example, 5 - 3 + 2 = 4 can be made true by adding parentheses: 5 - (3 + 2) = 0.

• Another example is 6 6 6 6 = 4 can be made true by using square root: √6 ÷ √6 + √6 - √6 = 4.

Array is a collection of elements stored in contiguous memory locations while linked list is a collection of nodes linked by pointers.

• Arrays have fixed size while linked lists can grow or shrink dynamically

• Insertion and deletion is faster in linked lists than arrays

• Accessing elements in arrays is faster than linked lists

• Arrays are better for random access while linked lists are better for sequential access

A linked list is used to store and manipulate a collection of data elements in a linear order.

• Linked lists are commonly used in computer science for implementing data structures like stacks, queues, and hash tables.

• They are also used in operating systems for managing memory allocation.

• For example, a linked list can be used to implement a music playlist where each song is a node and the links between nodes represent the order of the songs.

• Another example is a spell checker tha...read more

Implement a stack using a linked list

• Create a Node class with data and next pointer

• Create a Stack class with top pointer

• Push new nodes to the top of the stack

• Pop nodes from the top of the stack

• Check if the stack is empty before popping

Program to check if a binary tree is a BST

• Traverse the tree in-order and check if the values are in ascending order

• Use a min-max range for each node to check if it satisfies the BST property

• Recursively check if the left and right subtrees are BSTs