Zomato Software Development Engineer Interview Questions and Answers

Round duration - 60 minutes
Round difficulty - Easy

Two coding questions were given in the first round to be solved in 60 minutes.

Q1. 
Rearrange Array Elements Problem Statement
Given an array A containing 'N' integers and an integer m, rearrange the elements of the array such that the differences between the array elements and m are sor...read more
Ans. 
Rearrange array elements based on their differences from a given integer.
• Calculate the differences between each element and the given integer.

• Sort the elements based on their differences while maintaining the original order for elements with the same difference.

• Implement a function to rearrange the array elements as per the given criteria.
Answered by AI
Add your answer
Q2. 
Print Nodes at Distance K from a Given Node
Given an arbitrary binary tree, a node of the tree, and an integer 'K', find all nodes that are at a distance K from the specified node, and return a list of th...read more
Ans. 
The task is to find all nodes in a binary tree that are at a distance K from a given node.
• Traverse the binary tree to find the given node

• From the given node, perform a depth-first search to find all nodes at distance K

• Use a list to store the values of the nodes at distance K

• Return the list of values in any order
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Easy

This was a technical round with questions based on DSA, DBMS, Computer Networking and project based questions.

Q1. 
Triangle of Numbers Pattern
Ninja is tasked with printing a triangle pattern based on a given number 'N' for any test case.
Example:
Input:
N = 4
Output:
   1
  232
 34545
4567654
Explanation:
The pat...read more
Ans. 
Print a triangle pattern of numbers based on a given number 'N'.
• Iterate through each row and print the numbers accordingly

• Use spaces to center-align the numbers in each row

• Increment the numbers in each row as per the pattern
Answered by AI
Add your answer
Q2. What is the difference between a web server and an application server?
Ans. 
Web server serves static content over HTTP, while application server runs dynamic content and business logic.
• Web server handles HTTP requests and responses, serving static content like HTML, images, and CSS.

• Application server executes business logic, runs dynamic content, and interacts with databases.

• Web server examples include Apache, Nginx, while application server examples include Tomcat, JBoss.

• Web server focuses on...read more
Answered by AI
Add your answer
Q3. How does the internet work?
Ans. 
The internet is a global network of interconnected computers that communicate using standardized protocols.
• The internet is made up of a vast number of interconnected networks of computers.

• Data is transmitted over the internet using protocols such as TCP/IP.

• Websites are hosted on servers connected to the internet, and users access them using web browsers.

• Internet Service Providers (ISPs) provide access to the internet f...read more
Answered by AI
Add your answer
Q4. Write a SQL query to find the nth highest salary.
Ans. 
SQL query to find the nth highest salary
• Use the 'SELECT DISTINCT' statement to get unique salary values

• Order the salaries in descending order using 'ORDER BY' clause

• Use 'LIMIT' and 'OFFSET' to get the nth highest salary
Answered by AI
Add your answer

Round duration - 30 minutes
Round difficulty - Easy

Typical HR round with behavioral problems.

Round duration - 90 minutes
Round difficulty - Medium

 Around 65-70 people sat for the test. 15 people were shortlisted. It consisted of the following to be done in 90 minutes.

- 28 MCQs based on core CS 

- 2 Coding questions – everyone had different and random questions. Most questions were custom logic based (easy level) including some standard questions – LCS, LIS, topological sort.

Round duration - 60 minutes
Round difficulty - Easy

Interviewer was very friendly. It started with the standard – tell me about yourself / introduce yourself type of question. Then he proceeded and asked two coding questions

Q1. 
Remove Duplicates from a Sorted Linked List
Your friend has homework to complete. Help him by removing duplicates from a sorted linked list.
You are given the 'Head' of a sorted linked list. Modify the l...read more
Ans. 
Remove duplicates from a sorted linked list without adjacent duplicates.
• Traverse the linked list while comparing current and next nodes.

• If they are equal, skip the next node by updating the current node's next pointer.

• Repeat until the end of the list is reached.
Answered by AI
Add your answer
Q2. 
Course Schedule Problem Statement
You are enrolled as a student and must complete N courses, numbered from 1 to N, to earn your degree.
Some courses have prerequisites, which means that to take course i,...read more
Ans. 
Check if it is feasible to complete all courses with prerequisites.
• Create a graph representing the prerequisites with courses as nodes and edges as prerequisites.

• Perform a topological sort on the graph to check if there is a cycle (if there is, then it's not feasible to complete all courses).

• If there is no cycle, then it is feasible to complete all courses.
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

This round had only 1 question. The interviewer introduced himself. And he advised me to clearly understand the problem before proceeding.

Q1. 
LCA of Binary Tree Problem Statement
You are given a binary tree of distinct integers, along with two nodes, ‘X’ and ‘Y’. Your task is to determine the Lowest Common Ancestor (LCA) of ‘X’ and ‘Y’.
The LC...read more
Ans. 
Find the Lowest Common Ancestor of two nodes in a binary tree.
• Traverse the binary tree to find the paths from the root to nodes X and Y.

• Compare the paths to find the last common node, which is the Lowest Common Ancestor.

• Implement a recursive function to efficiently find the LCA.

• Handle cases where one node is an ancestor of the other.

• Consider edge cases like when X or Y is the root node.
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

Pretty Good Round. Fast Paced. We covered a lot of ground.

Q1. 
Binary Search Tree Iterator Problem Statement
Design and implement a class BSTIterator to perform an in-order traversal over a Binary Search Tree (BST). Your implementation should include the following me...read more
Ans. 
Design and implement a class BSTIterator to perform in-order traversal over a Binary Search Tree (BST).
• Implement a parameterized constructor to initialize the iterator with the root of the BST.

• Implement a method 'next()' to return the next smallest element in in-order traversal.

• Implement a method 'hasNext()' to check if there exists a next smallest element in traversal.

• Ensure the output is the in-order traversal of the
Answered by AI
Add your answer
Q2. 
Maximum Consecutive Ones Problem Statement
Given a binary array 'ARR' of size 'N', your task is to determine the maximum length of a sequence consisting solely of 1’s that can be obtained by converting at...read more
Ans. 
Find the maximum length of a sequence of 1's by converting at most K zeroes into ones in a binary array.
• Iterate through the array and keep track of the current window of 1's and zeroes.

• Use a sliding window approach to find the maximum length of consecutive 1's by flipping at most K zeroes.

• Update the window based on the number of zeroes flipped and keep track of the maximum length found so far.

• Return the maximum length ...read more
Answered by AI
Add your answer
Q3. 
BFS in Graph Problem Statement
You are given an undirected and disconnected graph G(V, E) having V vertices numbered from 0 to V-1 and E edges. Your task is to print its BFS traversal starting from the 0t...read more
Ans. 
BFS traversal of an undirected and disconnected graph starting from vertex 0.
• Start BFS traversal from vertex 0 and visit all connected nodes in sorted order.

• Use a queue to keep track of nodes to visit next.

• Keep a visited array to avoid revisiting nodes.

• Print the BFS traversal path as the nodes are visited.

• Example: For input V=5, E=4 and edges 0-1, 0-2, 1-3, 2-4, the BFS traversal will be [0, 1, 2, 3, 4].
Answered by AI
Add your answer
Q4. 
Dijkstra's Shortest Path Problem Statement
Given an undirected graph with V vertices (labeled 0, 1, ..., V-1) and E edges, each edge connects two nodes X and Y with a specified weight representing the dis...read more
Ans. 
Dijkstra's algorithm is used to find the shortest path distance from a source node to all other nodes in an undirected graph.
• Implement Dijkstra's algorithm to find the shortest path distance from node 0 to all other nodes in the graph.

• Use a priority queue to efficiently select the next node with the shortest distance.

• Initialize distances to all nodes as infinity, except for the source node which is 0.

• Update distances t...read more
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Hard

Bar Raised Round. Definitely felt the difficulty.

Q1. 
First Non-Repeating Character Problem Statement
You are given a string consisting of English alphabet characters. Your task is to identify and return the first character in the string that does not repeat...read more
Ans. 
Identify and return the first non-repeating character in a string, or the first character if all characters repeat.
• Iterate through the string to count the frequency of each character

• Iterate through the string again to find the first character with frequency 1

• If no such character is found, return the first character of the string
Answered by AI
Add your answer

Round duration - 150 minutes
Round difficulty - Medium

We could attempt at any time out of the 3 given days.
The round was very time constrained and we could NOT go back to the question that we already attempted.

Q1. 
Merge Two Sorted Linked Lists
Given two sorted linked lists, your task is to merge them into a single sorted linked list. Return the head of the newly combined list.
Note:
The given linked lists may or ...read more
Ans. 
Merge two sorted linked lists into a single sorted linked list.
• Create a dummy node to start the merged list

• Compare nodes from both lists and add the smaller one to the merged list

• Move the pointer of the merged list and the list with the smaller node

• Handle cases where one list is exhausted before the other

• Return the head of the merged list
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Hard

Evening at 5:00 pm. It was held on Amazon Chime app
Face cam was to be kept on COMPULSARILY. You could however not see the interviewer.
Codepen type environment was also used for typing my code which could be edited by the interviewer also.
(Shared document kind of)
Interviewer was very professional and was trying to push me towards getting the most optimal solution. Each and every answer was asked a counter question as to why I made that choice

Q1. 
Missing Numbers Problem Statement
You are provided with an array called ARR, consisting of distinct positive integers. Your task is to identify all the numbers that fall within the range of the smallest a...read more
Ans. 
Identify missing numbers within the range of smallest and largest elements in an array.
• Find the smallest and largest elements in the array.

• Generate a list of numbers within the range of smallest and largest elements.

• Remove the numbers that are present in the array to get the missing numbers.

• Sort and return the missing numbers.
Answered by AI
Add your answer
Q2. 
Find Maximum Element Between Two Nodes in a BST
Given a Binary Search Tree (BST) and two integers, NODE1 and NODE2, determine the maximum element found in the path between NODE1 and NODE2.
Explanation:
...read more
Ans. 
Find the maximum element between two nodes in a Binary Search Tree (BST) path.
• Traverse the BST to find the path between NODE1 and NODE2.

• Keep track of the maximum element encountered in the path.

• Return the maximum element found, or -1 if NODE1 or NODE2 are not in the BST or no elements exist between them.
Answered by AI
Add your answer
Q3. 
String Compression Problem Statement
Implement a program that performs basic string compression. When a character is consecutively repeated more than once, replace the consecutive duplicates with the coun...read more
Ans. 
Implement a program to compress a string by replacing consecutive duplicates with the count of repetitions.
• Iterate through the string and keep track of consecutive characters and their counts.

• Replace consecutive duplicates with the count of repetitions.

• Ensure the count of repetitions is ≤ 9.

• Return the compressed string.
Answered by AI
Add your answer

Round duration - 90 minutes
Round difficulty - Medium

Q1. 
Count Inversions Problem Statement
Given an integer array ARR of size N, your task is to find the total number of inversions that exist in the array.
An inversion is defined for a pair of integers in the...read more
Ans. 
Count the total number of inversions in an integer array.
• Iterate through the array and for each pair of elements, check if the conditions for inversion are met.

• Use a nested loop to compare each element with all elements to its right.

• Keep a count of the inversions found and return the total count at the end.
Answered by AI
Add your answer
Q2. 
Postfix Expression Evaluation Problem Statement
Given a postfix expression, your task is to evaluate the expression. The operator will appear in the expression after the operands. The output for each expr...read more
Ans. 
Evaluate postfix expressions by applying operators after operands. Return result modulo (10^9+7).
• Iterate through each character in the postfix expression

• If character is an operand, push it onto the stack

• If character is an operator, pop two operands from stack, apply operator, and push result back

• Continue until end of expression, return final result modulo (10^9+7)
Answered by AI
Add your answer

Round duration - 40 minutes
Round difficulty - Medium

Q1. 
String Rearrangement Problem Statement
You are given a string of lowercase characters. The objective is to rearrange (reorder) the string so that no two adjacent characters are identical.
Return the rear...read more
Ans. 
Given a string of lowercase characters, rearrange it so that no two adjacent characters are identical. Return the rearranged string or 'NO SOLUTION'.
• Iterate through the string and count the frequency of each character.

• Sort the characters based on their frequency in non-increasing order.

• Place the characters with highest frequency first, alternating with other characters.

• If there are more than half of the characters with
Answered by AI
Add your answer
Q2. 
Pair Sum Problem Statement
Given an integer array ARR of size N and an integer S, your task is to return a list of all pairs of elements such that the sum of each pair equals S.
Input:
The first line co...read more
Ans. 
The task is to find pairs of elements in an array that sum up to a given target value.
• Iterate through the array and for each element, check if the complement (target - current element) exists in a hash set.

• If the complement exists, add the pair to the result list.

• Ensure pairs are sorted based on the criteria mentioned in the question.
Answered by AI
Add your answer

Round duration - 40 minutes
Round difficulty - Medium

Q1. 
Find Number of Islands
You are provided with a 2-dimensional array/list of size N rows by M columns, containing ones (1) and zeroes (0). Here, 1 represents land, and 0 represents water.
A cell is consider...read more
Ans. 
Find the number of islands in a 2D matrix of 1s and 0s.
• Iterate through the matrix and perform depth-first search (DFS) to find connected 1s.

• Use a visited array to keep track of visited cells to avoid counting the same island multiple times.

• Increment the island count whenever a new island is encountered.
Answered by AI
Add your answer
Q2. 
Triplets in a Sorted Doubly Linked List
Given a sorted doubly linked list of distinct nodes, determine how many triplets in the list have a sum equal to a given value 'X'. Each node in the list contains a...read more
Ans. 
Given a sorted doubly linked list of distinct nodes, find and count triplets with a sum equal to a given value 'X'.
• Iterate through the list and for each node, use two pointers to find the other two nodes that sum up to 'X'.

• Keep track of the count of triplets found and return it at the end.

• Handle edge cases like when the list has less than 3 nodes or no triplets are found.
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

In this round i was tested for Data Structure competency. Two questions were asked.

Q1. 
Group Anagrams Problem Statement
Given an array or list of strings called inputStr, your task is to return the strings grouped as anagrams. Each group should contain strings that are anagrams of one anoth...read more
Ans. 
Group anagrams in an array of strings based on their characters.
• Iterate through the array of strings and sort each string to group anagrams together.

• Use a hashmap to store the sorted string as key and the list of anagrams as value.

• Return the values of the hashmap as the grouped anagrams.
Answered by AI
Add your answer

Round duration - 90 minutes
Round difficulty - Medium

Two questions were asked in this round on data structures and algorithms.

Q1. 
BST Iterator Problem Statement
You are tasked with creating a class named BSTIterator that acts as an iterator for the inorder traversal of a binary search tree. Implement the following functions:
1. BST...read more
Ans. 
Implement a BSTIterator class for inorder traversal of a binary search tree.
• Create a BSTIterator class with constructor, next, and hasNext functions.

• Use a stack to simulate inorder traversal of the binary search tree.

• Ensure the hasNext function returns true if there are more elements to traverse.

• Example: Input - 4 2 6 1 3 5 7 -1 -1 -1 -1 -1 -1, Output - 1 2 3 4 5 6 7
Answered by AI
Add your answer
Q2. 
K Most Frequent Words Problem Statement
Given an array or list WORDS of 'N' non-empty words and an integer 'K', identify the 'K' most frequent words and return them sorted by their frequency, in descendin...read more
Ans. 
Identify the K most frequent words in a list, sorted by frequency and lexicographical order.
• Use a hashmap to store word frequencies

• Use a min heap to keep track of K most frequent words

• Sort the heap based on frequency and lexicographical order
Answered by AI
Add your answer