SDE - 1 Myntra interview experience | Anonymous

Interview rounds

Round

Medium

Online Coding Interview

Duration120 minutes

Interview date12 May 2015

Coding problem2

This was a 2 hour round consisting of 5 mcqs and 2 codes. The mcqs were pretty much simple based on DS, DBMS, OS, OOP, and C.

1. Rabbit Jumping

Easy

20m average time

80% success

0/40

Asked in companies

You are given ‘n’ carrots numbered from 1 to ‘n’. There are k rabbits. Rabbits can jump to carrots only with the multiples of Aj(Aj,2Aj,3Aj…) for all rabbits from 1 to k.

Whenever Rabbit reaches a carrot it eats a little carrot. All rabbits start from the same beginning point. You have to determine the remaining carrots(i.e., carrots which are not eaten by any rabbit) after all rabbits reach the end.

Problem approach

The direct approach would be to mark all the carrots which are visited for each jumping factor. And print the number of non-visited carrots at the end.
So, we create an array of size N+1 (range 1-N).
Next, traverse the list of jumping factors and check which carrots are eatable for that particular factor. Mark all those carrots as visited.
Repeat this for all jumping factors and calculate the remaining uneaten carrots.

Try solving now

2. Flip Bits

Easy

15m average time

85% success

0/40

Asked in companies

You are given an array of integers ARR[] of size N consisting of zeros and ones. You have to select a subset and flip bits of that subset. You have to return the count of maximum one’s that you can obtain by flipping chosen sub-array at most once.

A flip operation is one in which you turn 1 into 0 and 0 into 1.

For example:

If you are given an array {1, 1, 0, 0, 1} then you will have to return the count of maximum one’s you can obtain by flipping anyone chosen sub-array at most once, so here you will clearly choose sub-array from the index 2 to 3 and then flip it's bits. So, the final array comes out to be {1, 1, 1, 1, 1} which contains five ones and so you will return 5.

Problem approach

Property of XOR can be used to solve this problem. 1^0 = 1 and 1^1 = 0
First, we calculate the number of digits in the given number using log.
Next, generate a number with digits equal to the digits in the given number and all bits set to 1.
The last step is to take the xor of the given number with the generated number.
The time complexity of this solution is O(log n).

Try solving now

Round

Medium

Video Call

Duration60 minutes

Interview date14 May 2015

Coding problem2

Started with a brief discussion on my projects and internships. A thorough discussion on whichever languages, frameworks I had used in my projects. Followed by discussion on coding questions. Apart from the codes there were some questions on OS, process stack, heap memory in Java, Garbage collection, OOP principles and comparison based sorting

1. Sum Of Max And Min

Easy

10m average time

90% success

0/40

Asked in companies

You are given an array “ARR” of size N. Your task is to find out the sum of maximum and minimum elements in the array.

Follow Up:

Can you do the above task in a minimum number of comparisons?

Problem approach

The direct solution would be to do a linear search and sequentially compare each element with the maximum and minimum element and keep updating accordingly. However, this approach takes ~2n comparisons.
To further reduce the number of comparisons, we can compare in pairs.
1. Traverse the array and pick 2 elements(a, b) at once.
2. Next, compare the two elements and update the min and max accordingly.
Let's say a>b, then : Update min by comparing (min, b) and max by comparing (max, a)
This approach would take ~ 3N/2 comparisons.

Try solving now

2. Invert a Binary Tree

Moderate

45m average time

55% success

0/80

Asked in companies

You are provided with a Binary Tree and one of its leaf nodes. You have to invert this binary tree. Inversion must be done by following all the below guidelines:

• The given leaf node becomes the root after the inversion.

• For a node (say, ‘x’) 
    ○ If there exists the left child that is not yet taken then this child must become the right child of ‘x’.
    ○ If the left child is already taken then the right child is still on the right side of ‘x’.

• The parent of ‘x’ must be the left child of ‘x’.

For Example:

Consider the above binary tree (image- before inversion), if the given leaf node is ‘1’ then the binary tree after inversion becomes exactly the same as given in the image representing after inversion.

Note:

The given binary tree will only have distinct values of nodes.

Try solving now

Round

Medium

Video Call

Duration60 minutes

Interview date14 May 2015

Coding problem4

Questions based on programming, DBMS and puzzles were asked in this round.

1. Rearrange Array Numbers to form Largest Possible Number

Moderate

35m average time

65% success

0/80

Asked in companies

You are given an array(ARR) of length 'N', consisting of non-negative integers. Using only these given numbers, rearrange the numbers in such a way that the resultant number thus formed is the largest possible. You cannot change the order of digits of a number.

For Example:

Given array numbers 12, 5, 34, the largest number you can form with them is 53412. There are other possible arrangements like 51234 or 34125, but they are both less than 53412.

Note:

As the final number formed after concatenation can be very large, print it as a string.

Problem approach

Sorting can be used to solve this problem.
First, we convert all the numbers to string type and insert them in a list.
Next, Sort the list of strings.
At last, concatenate all the strings to form the largest number.
This approach would take O(nlogn) time complexity.

Try solving now

2. Puzzle

Two boys A and B enter a tunnel . At 2/3rd of the tunnel, they see a train coming towards the tunnel ,the train is still at a distance from the tunnel . A runs back to that end of the tunnel from which they entered the tunnel, B runs towards the other end of the tunnel. Both of them just make it without being run over by the train . The train is travelling at a speed of 60kmph.Find the length of the tunnel

Problem approach

Tip 1: We need one more variable to solve this question. But that wont be told at the beginning,. We have to find out which variable that is.

3. DBMS Question

What is indexing?

Problem approach

Indexing is a data structure technique which is used to efficiently locate and access records from a database based on some attributes.

4. DBMS Question

Advantages of B+ Tree

Problem approach

1. Faster search queries as the data is stored only on the leaf nodes.
2. Records can be fetched in equal number of disk accesses.
3. We can access the data stored in a B+ tree sequentially as well as directly.

Round

Medium

Video Call

Duration45 minutes

Interview date15 May 2015

Coding problem3

Puzzles and HR based questions were asked in this round.
He asked questions like : what are my career goals, what do you look forward to in a boss , how do you see yourself in 5 years ,etc etc .

1. Puzzle

Given a biased coin, how would you take an unbiased decision .You don’t know whether it is biased towards heads or tails.

2. Puzzle

Given a cylindrical glass of water, how would you conclude whether it is more than half filled ,or less than half filled. The glass is not transparent and you do not have any measuring instrument. And you cannot spill out or add anything.

3. Puzzle

A man lives on the 12th floor . Everyday he uses the lift ,comes to the ground floor and goes to office. On his return ,three cases are seen:
1.Whenever he is with someone in the elevator he takes the lift directly to the 12th floor.
2.Whenever its raining he takes the elevator to the 12th floor.
3. On any non-rainy day when he is alone ,he takes the elevator to the 10th floor and walks up the stairs 2 floors.
Explain the situation.