MakeMyTrip Full Stack Developer Interview Questions, Process, and Tips

Round duration - 60 Minutes
Round difficulty - Medium

The test was in the morning at around 11.
It was on online assessment.
HackerEarth was perfect like everytime.\
MCQ were based on HTML ,CSS , JS, OOPS, SQL, Aptitude, OS.

Q1. 
Reach the Destination Problem Statement
You are given a source point (sx, sy) and a destination point (dx, dy). Determine if it is possible to reach the destination point using only the following valid mo...read more
Ans. Brute force approach
The naive approach to solve this problem is to consider each and every possible move until we reach the destination.
 
This can be done using recursion. Below is the algorithm:
 
• Check for the bases:
  • If the source and destination coordinates are the same, return true.
  • Return false, if the x (or y) coordinate of source point is greater than the x (or y) coordinate of the destination point. As the...read more
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Q2. 
Delete Node in Binary Search Tree Problem Statement
You are provided with a Binary Search Tree (BST) containing 'N' nodes with integer data. Your task is to remove a given node from this BST.
A BST is a ...read more
Ans. SUCCESSOR
When we delete a node, three possibilities arise:
 
1. Node to be deleted is a leaf node: Simply remove it from the tree.
2. Node to be deleted has only one child: Copy that child to the node and delete the child.
3. Node to be deleted has two children: Find the inorder successor of the node. Copy contents of the inorder successor to the node and delete the inorder successor.
 
The inorder successor of a node in BS...read more
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Round duration - 90 Minutes
Round difficulty - Hard

The interviewer was very friendly. He gave me problems one by one and asked me to write code for all of them in Code Pair round. Explain Scope and Scope Chain in javascript. What is a Stored Procedure in SQL?

Q1. 
Shortest Path in a Binary Matrix Problem Statement
Given a binary matrix of size N * M where each element is either 0 or 1, find the shortest path from a source cell to a destination cell, consisting only...read more
Ans. Backtracking
To find the shortest path in the Binary Matrix, we search for all possible paths in the Binary Matrix from the source cell to the destination cell until all possibilities are exhausted. We can easily achieve this with the help of backtracking.
 
We start from the given source cell in the matrix and explore all four paths possible and recursively check if they will lead to the destination or not. Out of a...read more
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Q2. 
Pair Sum Problem Statement
You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to find and return a list of all pairs of elements where each sum of a pair equals 'S'.
Note:
...read more
Ans. Brute Force
• Initialize a list to store our results.
• For each element in the array 'ARR[i]', check if ('ARR[i]' + ‘ARR[j]’), equals to given sum or not, where ‘i’ < ‘j’ < ‘N’.
• If the condition matches, add the pair('ARR[i]', ‘ARR[j]’) to the list. Sort the list of pairs as per the given output format and return this list.
Space Complexity: O(1)Explanation:
O(1).
 
Constant extra space is required.
Time Complexity: O...read more
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Q3. 
Validate Binary Search Tree (BST)
You are given a binary tree with 'N' integer nodes. Your task is to determine whether this binary tree is a Binary Search Tree (BST).
BST Definition:
A Binary Search Tr...read more
Ans. BST property
The approach is based on the fact that the value of each node in a BST is greater than the value of all the nodes in the left subtree and smaller than the value of all the nodes in the right subtree.
 
Here is the complete algorithm-
• For each node, we store the minimum and maximum value allowed for that node. Initially, for the root node, the minimum value would be -10^9 and the maximum value should be 10...read more
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Round duration - 45 minutes
Round difficulty - Medium

The round was with CTO level person. He was very friendly. What is the difference between SQL and MySQL? What are Constraints in SQL?

Q1. 
Longest Duplicate Substring Problem Statement
You are provided with a string 'S'. The task is to determine the length of the longest duplicate substring within this string. Note that duplicate substrings ...read more
Ans. Approach1
 The key idea is to find all possible substrings and keep the count of all substrings and return the length  longest substring which appears more than once.
 
Algorithm:
• Create an ans variable initial value 0.
• Run a loop from i = 0 to len of(string).
• Inside this loop run a from j = i to length(string).
• Check if the count of substring from i to j appears more than one time. If it appears more than one ...read more
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Q2. 
Maximum Sum of Products for Array Rotations
You are given an array ARR consisting of N elements. Your task is to determine the maximum value of the summation of i * ARR[i] among all possible rotations of ...read more
Ans. Brute Force
It’s important to note that, there are only a finite number of unique arrangments of the array possible after applying rotation operations on the array any number of times. So what we can do is find the sum(i*ARR[i]) for all possible rotations and return the maximum among them.
 
Here is the algorithm :
 
1. Create a variable (say, ‘maxSum’) and initialise it to 0.
2. Run a loop from 0 to 'N - 1' (say, iterat...read more
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Round duration - 90 minutes
Round difficulty - Easy

2 Coding Questions and 20 MCQ's to be solved in 90 minutes. It was from 6 pm. The camera and screen-recorders were on. The mcq was on web, oops, dbms.

Q1. 
Number of Islands II Problem Statement
You have a 2D grid of dimensions 'N' rows by 'M' columns, initially filled with water. You are given 'Q' queries, where each query contains two integers 'X' and 'Y'....read more
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Q2. 
Make Array Elements Equal Problem Statement
Given an integer array, your objective is to change all elements to the same value, minimizing the cost. The cost of changing an element from x to y is defined ...read more
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Round duration - 70 minutes
Round difficulty - Medium

The interview started with the interviewer asking me about my projects and why and what I have used in them. Be very clear with all the technologies you have used in your project as the interviewer will ask you in-depth about it.
Explain Components, Modules and Services in Angular. What is a Recursive Stored Procedure?

Q1. 
Sub Sort Problem Statement
You are given an integer array ARR. Determine the length of the shortest contiguous subarray which, when sorted in ascending order, results in the entire array being sorted in a...read more
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Q2. 
Minimum Operations Problem Statement
You are given an array 'ARR' of size 'N' consisting of positive integers. Your task is to determine the minimum number of operations required to make all elements in t...read more
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Q3. 
Tower of Hanoi Problem Statement
You have three rods numbered from 1 to 3, and 'N' disks initially stacked on the first rod in increasing order of their sizes (largest disk at the bottom). Your task is to...read more
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Q4. Can you explain the concepts of multithreading and semaphore in operating systems?
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Round duration - 30 minutes
Round difficulty - Easy

The interviewer was VP of Engineering at MakeMyTrip with more than 10 years of experience. He asked about the 4 Pillars of OOPS and we had an in-depth discussion with real-life applications for each of them.

Q1. 
Square Root with Decimal Precision Problem Statement
You are provided with two integers, 'N' and 'D'. Your objective is to determine the square root of the number 'N' with a precision up to 'D' decimal pl...read more
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Round duration - 120 Minutes
Round difficulty - Medium

There were two sections mcq's and coding. We were allowed to switch between sections and there was no specific time for any section. Around 350 students gave the test.

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. Brute Force Approach
The steps are as follows:
 
1. Initialize a ‘COUNT’ with 0 to keep track of the number of inversions
2. Iterate over every element in the array in a linear fashion starting from 0.
3. For every element, check all the elements ahead of the current element and check the condition.
   1. If the condition satisfies, increase the ‘COUNT’ by 1.
   2. Otherwise, move to the next iteration.
4. Return the ‘COUNT’.
Space Complexity: O(...read more
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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. Brute Force approach
The simplest way to find the required subarray would be to consider all the possible subarrays and compare the length at every point and store the longest length. If at any point, the current element is 0 and the value of ‘K’ is greater than 0, use it to convert the current element to 1. Else if the value of K is 0 , iterate further to find the next possible subarray.
 
Algorithm : 
1. Loop over...read more
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Round duration - 50 Minutes
Round difficulty - Medium

About 45 students were shortlisted for this round. My interview was at 10:15am. I was asked to introduce myself. 

Q1. 
Maximum Distance Problem Statement
Given an integer array 'A' of size N, your task is to find the maximum value of j - i, with the restriction that A[i] <= A[j], where 'i' and 'j' are indices of the ar...read more
Ans. Efficient approach
The idea behind this approach is to create a monotonously decreasing array and comparing its values with the given array to find the maximum distance.
• Create an auxiliary array ‘RMax’ such that ‘RMax’ holds the greatest element on the right side of the given array.
• Declare a variable ‘diff’ initialized to -1 to find the maximum distance.
• Now traverse both the arrays simultaneously from left to right and ...read more
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Q2. 
Determine the Left View of a Binary Tree
You are given a binary tree of integers. Your task is to determine the left view of the binary tree. The left view consists of nodes that are visible when the tree...read more
Ans. Preorder Traversal Approach
The idea is to use preorder traversal and for each level of the binary tree include the leftmost node in the answer. In the preorder traversal, we will traverse the left subtree of any node before the right subtree so that all nodes to the left of the current node are visited before the nodes which are on the right of the current node. Hence for any level, we will reach the leftmost node befo...read more
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Round duration - 40 Minutes
Round difficulty - Easy

About 17 students cleared the first round. My second round was at 4:30pm. The interviewer was very humble. 

Round duration - 20 Minutes
Round difficulty - Easy

This was HR round, 7 students were shortlisted for this round. I received the call after 6:30pm.