HealthifyMe Senior Software Engineer Interview Questions and Answers

Identify data structure based on insertion and deletion order

• If insertion and deletion follow LIFO order, it is a stack

• If insertion follows FIFO order and deletion follows LIFO order, it is a queue

• If insertion and deletion follow priority order, it is a priority queue

Find maximum element in an array in less than O(N)

• Use divide and conquer approach

• Compare maximum of left and right subarrays

• Recursively find maximum element

Binary Search has a time complexity of O(log n) and is derived from dividing the search space in half at each step.

• Binary Search is a search algorithm that works on sorted arrays.

• It starts by comparing the target value to the middle element of the array.

• If the target value is smaller, the search continues on the lower half of the array.

• If the target value is larger, the search continues on the upper half of the array.

• T...read more

QuickSort is a sorting algorithm that uses divide and conquer approach.

• Choose a pivot element from the array

• Partition the array into two sub-arrays, one with elements less than the pivot and one with elements greater than the pivot

• Recursively apply the above steps to the sub-arrays

• Combine the sorted sub-arrays to get the final sorted array

Code for Fibonacci Series using Recursion, Iteration and Dynamic Programming

• Recursion: Define a function that calls itself with the previous two numbers in the series as arguments

• Iteration: Use a loop to calculate the series by adding the previous two numbers in each iteration

• Dynamic Programming: Store the previous two numbers in variables and use them to calculate the next number in the series

Implementing a Queue using Stacks

• Use two stacks to implement a queue

• Push elements onto the first stack

• When dequeuing, pop all elements from the first stack and push onto the second stack

• Pop the top element from the second stack to dequeue

• If the second stack is empty, pop all elements from the first stack and push onto the second stack

MergeSort is a divide and conquer algorithm that sorts an array of strings.

• Divide the array into two halves

• Recursively sort the two halves

• Merge the sorted halves

Counting Sort is a sorting algorithm that sorts elements by counting the number of occurrences of each unique element.

• Count the occurrences of each element in the array

• Calculate the cumulative sum of the counts

• Place each element in the sorted array based on its count and cumulative sum

• Time complexity is O(n+k) where n is the number of elements and k is the range of input

• Example: Sort an array of strings based on their

Chrome uses an algorithm to predict and suggest words based on user input.

• Chrome's algorithm uses a combination of user history, bookmarks, and popular searches to predict and suggest words.

• The algorithm also takes into account the frequency and recency of the user's input.

• Chrome's suggestion feature is powered by Google's Autocomplete API, which uses machine learning to predict and suggest words.

• The suggestions are di...read more

Queue can be implemented using two stacks by maintaining the order of elements in the stacks.

• Create two stacks, let's call them stack1 and stack2

• When an element is enqueued, push it to stack1

• When an element is dequeued, pop all elements from stack1 and push them to stack2

• Pop the top element from stack2 and return it as the dequeued element

• If stack2 is empty, repeat step 3

• To get the front element of the queue, peek the

Left join returns all records from left table and matching records from right table. Full outer join returns all records from both tables.

• Left join is used to combine two tables based on a common column.

• In left join, all records from the left table are returned along with matching records from the right table.

• If there is no match in the right table, NULL values are returned.

• Example: SELECT * FROM table1 LEFT JOIN table...read more

Magic functions are special methods in PHP that start with __. Autoloading is a way to automatically load classes.

• Magic functions are used to handle certain events in PHP, such as object creation or property access.

• Autoloading allows PHP to automatically load classes when they are needed, without requiring manual includes.

• Magic functions can be used in conjunction with autoloading to dynamically load classes or handle

Given three sorted arrays, find common elements.

• Create three pointers to traverse each array

• Compare the elements at the pointers and move the pointer of the smallest element

• If all pointers point to the same element, add it to the result and move all pointers

• Repeat until any pointer reaches the end of its array

Check if a number is a power of 2 or not.

• A power of 2 has only one bit set in its binary representation.

• Use bitwise AND operator to check if the number is a power of 2.

• If n is a power of 2, then n & (n-1) will be 0.

Event bubbling is the propagation of an event from the innermost child element to the outermost parent element.

• Events triggered on a child element will also trigger on its parent elements

• The event travels up the DOM tree until it reaches the document object

• Can be stopped using event.stopPropagation()

• Can be useful for event delegation

The .on('click',function() is a more flexible method than .click(function())

• The .on() method can handle multiple events and selectors

• The .click() method can only handle one event and one selector

• The .on() method can also handle dynamically added elements

• The .click() method cannot handle dynamically added elements

Function to check if two strings are anagram or not

• Create two character arrays from the strings

• Sort the arrays

• Compare the sorted arrays

Function to determine the order of integers in an array.

• Check first and last element to determine if increasing or decreasing

• Check for inflection point to determine if order changes

• Return order type as string

Optimize images, minify code, reduce HTTP requests, use caching, and lazy loading.

• Optimize images using compression and appropriate file formats

• Minify code to reduce file size and improve load times

• Reduce HTTP requests by combining files and using sprites

• Use caching to store frequently accessed data locally

• Implement lazy loading to defer loading of non-critical resources

Design a database schema for a movie site with user ratings and recommendations.

• Create tables for movies, users, ratings, and recommendations

• Use foreign keys to link tables

• Include columns for movie genre and user watch history

• Algorithm for recommendations can use user watch history and ratings to suggest similar movies

Function to simulate dice roll with equal probability without using random function

• Use a toss function that returns either 0 or 1 with equal probability

• Call the toss function 3 times and convert the result to a binary number

• If the binary number is greater than 0 and less than or equal to 6, return it

• If the binary number is greater than 6, repeat the process

Query to fetch duplicate email from table

• Use GROUP BY and HAVING clause to filter out duplicates

• SELECT email, COUNT(*) FROM table_name GROUP BY email HAVING COUNT(*) > 1;

• This will return all the duplicate emails in the table