10+ Wizni Software Interview Questions and Answers

A code to find the frequency of every character in a string.

• Create an empty dictionary to store the frequency of each character.

• Iterate through the string and for each character, check if it is already in the dictionary.

• If it is, increment its value by 1. If it is not, add it to the dictionary with a value of 1.

• Return the dictionary with the frequency of each character.

Use the formula for sum of first n natural numbers to find the missing number in the array.

• Calculate the sum of first n natural numbers using the formula n*(n+1)/2

• Calculate the sum of all numbers in the array

• Subtract the sum of array from the sum of first n natural numbers to find the missing number

Delete and truncate are SQL commands used to remove data from a table, but they differ in their functionality.

• DELETE command is used to remove specific rows from a table based on a condition

• TRUNCATE command is used to remove all the rows from a table

• DELETE command can be rolled back, while TRUNCATE command cannot be rolled back

• DELETE command is slower than TRUNCATE command

• DELETE command can be used with or without a WHERE clause, while TRUNCATE command cannot be used with a W...read more

Finding middle element in linked list using Floyd algorithm.

• Floyd algorithm uses two pointers, one slow and one fast, to traverse the linked list.

• The slow pointer moves one node at a time while the fast pointer moves two nodes at a time.

• When the fast pointer reaches the end of the list, the slow pointer will be at the middle element.

• If the list has even number of elements, there will be two middle elements.

• In that case, we can return either of the two middle elements.

The question involves two tasks: moving all zeroes to the end of an array and counting the frequency of characters in a string.

• To move all zeroes to the end of an array, iterate through the array and keep track of the non-zero elements. Then, fill the remaining positions with zeroes.

• To count the frequency of characters in a string, iterate through the string and use a dictionary or array to store the count of each character.

To swap two numbers without using a third variable, use arithmetic operations.

• Use addition and subtraction to swap the numbers. For example, a=5, b=10. a=a+b, b=a-b, a=a-b will swap the values.

• Another method is to use XOR operation. For example, a=5, b=10. a=a^b, b=a^b, a=a^b will swap the values.

Abstraction can be achieved by hiding unnecessary details and only exposing essential features.

• Identify the essential features of the system

• Hide unnecessary details by encapsulating them

• Use interfaces to define essential features

• Implement the interfaces to provide functionality

• Example: A car's interface is the steering wheel, pedals, and dashboard. The engine and transmission are encapsulated.

• Example: A software interface is a public method that exposes functionality while hi...read more

Data structures like arrays and linked lists are used in real life applications such as social media networks, databases, and GPS systems.

• Social media networks use arrays to store user profiles and linked lists to manage friend connections.

• Databases use data structures like B-trees and hash tables to efficiently store and retrieve data.

• GPS systems use graphs to represent road networks and find the shortest path between locations.

OOPS concept - Inheritance

• Inheritance is a mechanism in OOPS where a new class is derived from an existing class

• The new class inherits all the properties and behavior of the existing class

• It allows code reusability and helps in creating a hierarchy of classes

• Example: A class 'Car' can be inherited by a class 'SUV' which will have all the properties of 'Car' and additional properties specific to 'SUV'

• Inheritance can be of different types - single, multiple, multilevel, hierarc...read more

Some of the latest technologies right now include artificial intelligence, machine learning, blockchain, Internet of Things (IoT), and 5G.

• Artificial intelligence (AI) - used in various industries for automation and decision-making

• Machine learning - subset of AI that enables systems to learn and improve from experience

• Blockchain - decentralized and secure way of storing and sharing data

• Internet of Things (IoT) - network of interconnected devices that can communicate and share ...read more

Reverse a linked list by changing the direction of pointers

• Start from the head of the linked list

• Iterate through the list and change the direction of pointers to reverse the list

• Update the head to point to the last node as the new head