Business Analyst Snapdeal interview experience

Interview rounds

Round

Easy

Coding Test - Pen and paper

Duration40 minutes

Interview date16 Mar 2015

Coding problem0

The first round was the written test. There were 8 theoretical questions asked in the paper. The questions were either in the form of puzzles or probability based questions. The first three questions in the paper were compulsory questions and needed to be answered correctly for the rest of your paper to be evaluated; if a particular candidate answered any one of these questions incorrectly then he was rejected then and there. Apart from these 3 questions solving 2 more questions would have assured a candidate’s chance of getting selected for the next round. The duration of the test was of around 40 minutes.

Round

Easy

Face to Face

Duration60 minutes

Interview date16 Mar 2015

Coding problem3

In the interview I was asked few puzzles and few coding problems.
In the coding questions the interviewers did not ask me to write down the complete codes of the problems, they only asked me to suggest some suitable algorithms.

1. Puzzle

Three couples are on the vacation.They need to cross the river to reach their hotel. There are 3 rules which are as follows:-
Rule 1:- The boat can only carry two people at a time. If the third person trying to get in the boat then the boat will sink.
Rule 2:- The husbands are so jealous that they can not let their wife with another man, without their presence.
Rule 3:- The boat cannot run on itself. At-least one person should be on the boat to go from one side to another.

How many trips does it take them to all get across the river?

Problem approach

Let the 3 couples have wore green, red and blue dresses.So, there should be green wife and green husband, red wife and red husband, blue wife and blue husband.

Step 1:-Green couple will go to the hotel side and green husband will return with the boat.(2 moves)

Step 2:-Now red wife and blue wife will go to the hotel side and red wife will return with the boat.(2 moves)

Step 3:-Green husband and blue husband will go to the hotel side and blue couple will return with the boat.(2 moves)

Step 4:-Red husband and blue husband will go to the hotel side and green wife will return with the boat.(2 moves)

Step 5:-Red wife and blue wife will go to the hotel side and blue wife will return with the boat.(2 moves)

Step 6:-Finally, blue wife and red wife will go the hotel side.(1 move)

So, there will be a total of 11 steps.

2. Puzzle

How do we measure forty-five minutes using two identical wires, each of which takes an hour to burn? We have matchsticks with us. The wires burn non-uniformly.

Problem approach

If we light a stick, it takes 60 minutes to burn completely. What if we light the stick from both sides? It will take exactly half the original time, i.e. 30 minutes to burn completely.
0 minutes – Light stick 1 on both sides and stick 2 on one side.
30 minutes – Stick 1 will be burnt out. Light the other end of stick 2.
45 minutes – Stick 2 will be burnt out. Thus 45 minutes is completely measured.

3. Count set bits in an integer

Hard

15m average time

85% success

0/120

Asked in companies

You are given a positive integer ‘N’. Your task is to find the total number of ‘1’ in the binary representation of all the numbers from 1 to N.

Since the count of ‘1’ can be huge, you are required to return it modulo 1e9+7.

Note:

Do not print anything, just return the number of set bits in the binary representation of all integers between 1 and ‘N’.

Problem approach

A simple method would be to Loop through all bits in an integer, check if a bit is set and if it is, then increment the set bit count.
Time Complexity: Θ(logn)
Auxiliary Space: O(1)

Efficient approach would be to use Brian Kernighan’s Algorithm.
Algorithm :
1) Initialize count: = 0

2) If integer n is not zero
(a) Do bitwise & with (n-1) and assign the value back to n
n: = n&(n-1)
(b) Increment count by 1
(c) go to step 2

3) Else return count.

Try solving now

Round

Easy

Face to Face

Duration45 minutes

Interview date16 Mar 2015

Coding problem2

In second round of interview I was asked some hardcore programming questions on data structures since I wrote it as my area of interest.
I was asked some puzzles as well.

1. Merge two sorted arrays

Moderate

15m average time

85% success

0/80

Asked in companies

Ninja has been given two sorted integer arrays/lists ‘ARR1’ and ‘ARR2’ of size ‘M’ and ‘N’. Ninja has to merge these sorted arrays/lists into ‘ARR1’ as one sorted array. You may have to assume that ‘ARR1’ has a size equal to ‘M’ + ‘N’ such that ‘ARR1’ has enough space to add all the elements of ‘ARR2’ in ‘ARR1’.

For example:

‘ARR1’ = [3 6 9 0 0]
‘ARR2’ = [4 10]
After merging the ‘ARR1’ and ‘ARR2’ in ‘ARR1’. 
‘ARR1’ = [3 4 6 9 10]

Problem approach

A simple approach would be to create a new arrays with size as sum of the sizes of both the arrays. Copy the elements of both the arrays in the new array and sort the array.
A space optimized approach also exists. While traversing the two sorted arrays parallelly, if we encounter the jth second array element is smaller than ith first array element, then jth element is to be included and replace some kth element in the first array.

Algorithm :
1) Initialize i,j,k as 0,0,n-1 where n is size of arr1

2) Iterate through every element of arr1 and arr2 using two pointers i and j respectively
if arr1[i] is less than arr2[j]
increment i
else
swap the arr2[j] and arr1[k]
increment j and decrement k

3) Sort both arr1 and arr2

Try solving now

2. Puzzle

There are three equal rows that consist of three dots each. What you have to do is to draw four straight lines to connect all of the dots. However, the challenge is to avoid lifting the pencil off the paper.

Problem approach

Step 1. Draw a straight line down from the very first dot (in other words, draw a left side of the square), but make it a bit longer, as if there was the fourth dot below;

Step 2. From this point, you lead the next line to the last dot of the second column and then to the second dot of the third column. And again, draw a longer line, imagine that there is one more dot in this direction;

Step 3. Now you need to draw a straight line from right to left, crossing the top row of the square;

Step 4. The last step is to draw a diagonal line from the very first dot to the last one, going through the center of the square.