System Engineer IBM interview experience | Anonymous

Interview rounds

Round

Medium

Online Coding Interview

Duration60 minutes

Interview date17 Sep 2021

Coding problem5

There were around 5-6 coding questions. The difficulty was about easy to medium. Also there was 10 mcq DSA questions

1. Sort Stack

Easy

20m average time

80% success

0/40

Asked in companies

You are given a stack ‘S’. Your task is to sort the sack recursively.

Note:

Looping through the stack is not allowed.
You need to return a stack that is sorted in descending order.

For example:

Given stack S = 1 3 2 
The output will be 3 2 1 since it is the sorted order.

Problem approach

The idea of the solution is to hold all values in Function Call Stack until the stack becomes empty. When the stack becomes empty, insert all held items one by one in sorted order. Here sorted order is important.

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2. Anagram Pairs

Moderate

30m average time

60% success

0/80

Asked in companies

You are given two strings 'str1' and 'str1'.

You have to tell whether these strings form an anagram pair or not.

The strings form an anagram pair if the letters of one string can be rearranged to form another string.

Pre-requisites:

Anagrams are defined as words or names that can be formed by rearranging the letters of another word. Such as "spar" can be formed by rearranging letters of "rasp". Hence, "spar" and "rasp" are anagrams.

Other examples include:

'triangle' and 'integral'
'listen' and 'silent'

Note:

Since it is a binary problem, there is no partial marking. Marks will only be awarded if you get all the test cases correct.

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3. Maximum in Subarrays of length K

Easy

27m average time

0/40

Asked in companies

Given an array of integers of size N and a number K, print the maximum value of each subarray of length K in the array

Problem approach

The idea is very basic run a nested loop, the outer loop which will mark the starting point of the subarray of length k, the inner loop will run from the starting index to index+k, k elements from starting index and print the maximum element among these k elements.

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4. Rearrange Alternatively

Easy

15m average time

85% success

0/40

Asked in companies

Given an array arr of size N containing positive and negative integers. Arrange the array alternatively such that every non-negative integer is followed by a negative integer and vice-versa.

Note:

The number of positive integers and negative integers may not be equal. In such cases, add the extra integers at the end.

For Example:

For array {4, -9, -2, 6, -8}, the output will be {-9, 4, -2, 6, -8}

For array {1, 2, 3, -5}, the output will be {-5, 1, 2, 3}

Problem approach

The idea is to use an auxiliary array. We maintain two pointers one to leftmost or smallest element and other to rightmost or largest element. We move both pointers toward each other and alternatively copy elements at these pointers to an auxiliary array. Finally, we copy the auxiliary array back to the original array.

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5. Rotate array

Easy

25m average time

80% success

0/40

Asked in companies

Given an array 'arr' with 'n' elements, the task is to rotate the array to the left by 'k' steps, where 'k' is non-negative.

Example:

'arr '= [1,2,3,4,5]
'k' = 1  rotated array = [2,3,4,5,1]
'k' = 2  rotated array = [3,4,5,1,2]
'k' = 3  rotated array = [4,5,1,2,3] and so on.

Problem approach

leftRotate(arr[], d, n)
start
For i = 0 to i < d
Left rotate all elements of arr[] by one
end

To rotate by one, store arr[0] in a temporary variable temp, move arr[1] to arr[0], arr[2] to arr[1] …and finally temp to arr[n-1]
Let us take the same example arr[] = [1, 2, 3, 4, 5, 6, 7], d = 2
Rotate arr[] by one 2 times
We get [2, 3, 4, 5, 6, 7, 1] after first rotation and [ 3, 4, 5, 6, 7, 1, 2] after second rotation.

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Round

Easy

Video Call

Duration30 minutes

Interview date18 Sep 2021

Coding problem5

This round was cogitative ability round. It is a type of test that aims at measuring a student’s intellect through games. Also termed as ‘Cognify’, these games are structured in a way that evaluate your personality and aptitude abilities.

There were around 5-6 game problem , we have to solve them in 30-35 minutes. This round is an elimination round.

After this round there was English Language Test round . This round came just after I cleared 2nd round. I have to answer as many questions in 15 minutes.. The questions were of type Antonyms , Synonyms , Jumbled Sentences, Verbal Ability Questions

1. Puzzle

Shortcuts :-
In Shortcuts, I need to move the blue marble to the starred area. There are some numbers available on the track. When you move any marble, the number on the track will be added to the distance traveled. There will be some red marbles too which will act as an obstacle in the path and you have to fix them too. The aim of this task is to move blue marbles to the stars with the minimum distance traveled. There will be three categories to evaluate your performance i.e, Ok, Good and Great.

2. Puzzle

In this game, I have to fit the blocks into the given grid. You can rotate the blocks too to fix them in the grid.

3. Puzzle

In this game, there will be a target value and some balloons presented on the screen. you have to click only that balloons that result in the same value as the target. Try to hit the maximum correct balloons.

4. Puzzle

In Resemble, we need to mentally rotate the image on the left and then replicate it on the right

5. Puzzle

In Proof it, we must identify as many misspelled words and punctuation error as possible in the time provided.

Round

Medium

Video Call

Duration30-45 minutes

Interview date21 Sep 2021

Coding problem2

This round was technical + HR round . DSA , DBMS, coding questions were asked.
Basic HR questions like about my project, about internships, why I want to join IBM . This type of questions were asked by HR

1. Minimum Number of Platform Needed

Easy

23m average time

85% success

0/40

Asked in companies

You are given the arrival and departure times of N trains at a railway station in a day. You need to find the minimum of platforms required for the railway station such that no train waits i.e No train should wait for the platform to be clear or free.

Problem approach

The idea is to take every interval one by one and find the number of intervals that overlap with it. Keep track of the maximum number of intervals that overlap with an interval. Finally, return the maximum value.

Follow the steps mentioned below:

Run two nested loops, the outer loop from start to end and the inner loop from i+1 to end.
For every iteration of the outer loop, find the count of intervals that intersect with the current interval.
Update the answer with the maximum count of overlap in each iteration of the outer loop.
Print the answer.

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2. Minimum number of swaps required to sort an array

Easy

10m average time

90% success

0/40

Asked in companies

You have been given an array 'ARR' of 'N' distinct elements.

Your task is to find the minimum no. of swaps required to sort the array.

For example:

For the given input array [4, 3, 2, 1], the minimum no. of swaps required to sort the array is 2, i.e. swap index 0 with 3 and 1 with 2 to form the sorted array [1, 2, 3, 4].

Problem approach

This can be easily done by visualizing the problem as a graph. We will have n nodes and an edge directed from node i to node j if the element at i’th index must be present at j’th index in the sorted array.

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