Invest4Edu Interview Questions and Answers

Binary heap is used to implement a priority queue.

• Binary heap is a complete binary tree where each node has a value greater than or equal to its children.

• It can be implemented using arrays, where the parent of node at index i is at index (i-1)/2.

• Insertion and deletion operations have time complexity of O(log n) in a binary heap.

Creating custom hook, explaining virtual DOM, sorting an array in React

• To create a custom hook in React, you can define a function that starts with 'use' and can be reused across components.

• React's virtual DOM is a lightweight copy of the actual DOM, which allows React to efficiently update the real DOM.

• To sort an array in JavaScript, you can use the built-in 'sort' method or write a custom sorting function.

Use a SQL query to find the second highest marks in a student database.

• Use the ORDER BY clause to sort the marks in descending order

• Use the LIMIT clause to limit the result to the second row

A binary tree can have any number of nodes, but the maximum number of trees with n nodes is 2^n.

• A binary tree can have 0 nodes, 1 node, 2 nodes, or any number of nodes.

• The maximum number of binary trees with n nodes is 2^n.

• For example, a binary tree with 3 nodes can have up to 8 different structures.

Program to check if two strings are anagrams

• Create a function that takes in two strings as input

• Remove any spaces and convert both strings to lowercase for consistency

• Sort the characters in both strings and compare if they are equal to determine if they are anagrams

• Example: 'listen' and 'silent' are anagrams

React's virtual DOM is a lightweight copy of the actual DOM, used for efficient updates and rendering.

• Virtual DOM is a representation of the actual DOM in memory.

• React compares the virtual DOM with the actual DOM to determine the minimal changes needed for updates.

• Changes are then batched and applied to the actual DOM for efficient rendering.

Sort elements of an array of strings

• Use a sorting algorithm like quicksort, mergesort, or bubblesort

• Ensure the sorting algorithm is implemented correctly for strings

• Consider using built-in sorting functions in programming languages like sort() in Python

Bubble sort has a time complexity of O(n^2) in the worst case scenario.

• Bubble sort compares adjacent elements and swaps them if they are in the wrong order.

• It continues to iterate through the array until no more swaps are needed.

• The worst case time complexity of bubble sort is O(n^2) where n is the number of elements in the array.

• Example: If we have an array of 5 elements, bubble sort would take 25 comparisons in the worst case.