OLX Desktop Support Engineer Interview Questions and Answers

Function to check if a string of parenthesis is balanced

• Use a stack to keep track of opening parenthesis

• If a closing parenthesis is encountered, pop from stack and check if it matches

• If stack is empty and a closing parenthesis is encountered, return False

• If all parenthesis are matched and stack is empty, return True

Count the occurrences of words in a paragraph.

• Split the paragraph into words using whitespace as a delimiter.

• Create a dictionary to store the count of each word.

• Iterate through the words and increment the count in the dictionary.

• Return the dictionary with the word counts.

Find common elements out of two sorted array

• Use two pointers to traverse both arrays simultaneously

• Compare elements at each pointer and move the pointer of the smaller element

• If elements are equal, add to common elements list and move both pointers

• Stop when either pointer reaches end of array

Convert a Binary Search Tree to a Doubly Linked List.

• Create a DLL node class with left, right, and data fields.

• Traverse the BST in-order and add each node to the DLL.

• Adjust the left and right pointers of each node to create the DLL.

• Return the head of the DLL.

The task is to fill the 'next' field of each node in a binary tree to point to the next node at the same level.

• Use a level order traversal to process the tree nodes.

• Maintain a queue to store the nodes at each level.

• For each node, set its 'next' field to the next node in the queue.

• If a node is the last node at its level, set its 'next' field to NULL.

To find anagrams of a given word in a dictionary, use a hash table to store sorted versions of each word as keys and their corresponding original words as values.

• Create a hash table to store the anagrams

• Iterate through each word in the dictionary

• Sort the characters of the word and use it as a key in the hash table

• If the key already exists, add the word to the list of values for that key

• Print the list of values for the

Suggest a data structure for efficient search of a string in 10 files and print line number and file if string appears more than once.

• Use a hash table to store the file name and line number of each occurrence of the string.

• Iterate through each file and for each line, check if the string is present and update the hash table accordingly.

• Print the hash table entries for the string.

Amazon is the right place for me because of its innovative culture, vast resources, and opportunities for growth.

• Amazon's innovative culture aligns with my passion for pushing boundaries and finding creative solutions.

• The company's vast resources provide the necessary tools and support to develop and deliver high-quality software.

• Amazon offers numerous opportunities for growth and career advancement, allowing me to con...read more

Boundary traversal of a tree is the process of visiting the nodes on the boundary of a tree in a specific order.

• The boundary traversal can be done in three steps: left boundary, leaf nodes, and right boundary.

• For the left boundary, start from the root and traverse down the left side of the tree until reaching a leaf node.

• For the leaf nodes, perform an inorder traversal to visit all the leaf nodes of the tree.

• For the ri...read more

Find the nearest greater value of a given value in a Binary Search Tree (BST).

• Start from the root node and compare the given value with the current node's value.

• If the given value is less than the current node's value, move to the left subtree.

• If the given value is greater than the current node's value, move to the right subtree.

• Keep track of the closest greater value encountered while traversing the tree.

• Return the cl

Given an infinite staircase with a broken kth step, find the maximum height we can reach in n rounds of jumping i steps.

• We can start by jumping the maximum number of steps in each round until we reach the broken step.

• After reaching the broken step, we can discard the i steps that would land us on the broken step and jump the remaining steps.

• We can continue this pattern until we reach the maximum height we can reach wit

Find sum of k smallest numbers in a BST.

• Traverse the BST in-order and add the k smallest numbers to a sum variable.

• Use a priority queue to keep track of the k smallest numbers.

• If k is greater than the number of nodes in the BST, return the sum of all nodes.

• If k is 0, return 0.

Design algorithm and database for seat booking system of BookMyShow and handle failed payments.

• Create a database with tables for movies, theaters, seats, bookings, and payments

• Use a locking mechanism to prevent double booking of seats

• If payment fails, release the locked seats and notify the user

• Write a query to get the timestamp in SQL: SELECT CURRENT_TIMESTAMP;

Code for time stamp in C

• Use the time.h header file

• Call the time() function to get the current time in seconds

• Convert the time to a string using strftime() function

• Use the format string to specify the desired format of the time stamp

Rearrange array in consecutive pair multiplication in descending order.

• Create a new array to store the multiplied values

• Use a loop to iterate through the original array and multiply consecutive pairs

• Write a compare function to sort the new array in descending order

Code to rearrange an array in maximum-minimum form.

• Sort the array in descending order.

• Create a new array and alternate between adding the maximum and minimum values from the sorted array.

• Return the new array.

• Time complexity: O(nlogn)

• Space complexity: O(n)

stoi() function converts a string to an integer.

• stoi() is a C++ function that takes a string as input and returns an integer.

• It is used to convert a string of digits into an integer.

• It can also handle negative numbers and ignore leading whitespace.

• Example: int num = stoi("123"); // num is now 123

Code for finding the longest common substring in an array of strings.

• Iterate through the first string and check for all possible substrings

• Check if the substring is present in all other strings

• Keep track of the longest common substring found so far

• Return the longest common substring

Answers to common technical questions in a software engineering interview

• A transaction in DBMS is a sequence of operations that must be treated as a single unit of work. ACID properties ensure reliability and consistency of transactions.

• A thread is a lightweight process that shares memory and resources with other threads in the same process. A process is a separate instance of a program.

• Common Linux commands include ls...read more