Saber Software Developer Intern Interview Questions and Answers

3 questions of medium to hard coding questions.

Q1. Technical interview including SQL, one programming language, and dbms based questions. the interview went well and was of 90mins.
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Round duration - 60 Minutes
Round difficulty - Easy

Asked every question possible from resume

Q1. Merge Sort
Given a sequence of numbers ‘ARR’. Your task is to return a sorted sequence of ‘ARR’ in non-descending order with help of the merge sort algorithm.
Example :
Merge Sort Algorithm -

Merge sor...read more
Ans. Recursion
The basic idea is that we divide the given ‘ARR’ into two-part call them ‘leftHalves’ and ‘rightHalves’ and call the same function again with both the parts. In the end, we will get sorted ‘leftHaves’ and sorted ‘righthalves’ which we merge both of them and return a merged sorted ‘ARR’.
We implement this approach with a divide and conquer strategy.
 
Here is the algorithm : 
 
1. Divide ‘ARR’ into two-p...read more
Answered by CodingNinjas
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Q2. Cycle Detection in a Singly Linked List
You have given a Singly Linked List of integers, determine if it forms a cycle or not.
A cycle occurs when a node's next points back to a previous node in the ...read more
Ans. Outer And Inner Loop
We are going to have two loops outer-loop and inner-loop 
1. Maintain a count of the number of nodes visited in outer-loop.
2. For every node of the outer-loop, start the inner loop from head.
3. If the inner-loop visits the node next to the outer-loop node, then return true, else repeat the process for the next iteration of outer-loop.
4. If outer-loop reaches the end of list or null, then return false.
Space ...read more
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Q3. SQL Questions
Asked usages of different queries. How to do same operation using two queries, nested queries and joins etc
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Round duration - 60 Minutes
Round difficulty - Medium

Q1. Technical Questions
Asked me to explain my projects briefly and also asked lot of cross question
what is polymorphism, abstract methods and classes
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Q2. System Design Question
asked low level design of e-commerce website
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Round duration - 90 minutes
Round difficulty - Medium

It consist three question - first que is of related to tree and i gave difficulty level of this question as hard. second que is of based on logical and reasoning , it is medium level question and third que can be done by map and it is also medium level que.
In codility platform we are not able to see hidden test cases whether it is satisfied or not . we just have to submit after passing sample testcases.

Q1. Minimum number of swaps required to sort an array
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.
F...read more
Ans. Naive Approach
While iterating over the array, check the current element, and if not in the correct place, replace that element with the index of the element which should have come in this place.
 
Below is the algorithm:
1. Create a copy of the given input array and store it in temp.
2. Sort the temp array.
3. Iterate over the input array, and check whether the current element is at the right place or not by comparing it with t...read more
Answered by CodingNinjas
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Q2. Maximum sum of non-adjacent elements
You are given an array/list of ‘N’ integers. You are supposed to return the maximum sum of the subsequence with the constraint that no two elements are adjacent in the ...read more
Ans. Recursive Approach (top down)
We are going to explore all the possibilities of subsequences in which there will be no two elements that are adjacent to one another in the given array/list. So if we take the current element, let’s say ‘CURR’ then we are not allowed to take the element adjacent to ‘CURR’. So for that, we will call a recursive function one step forward to the ‘CURR’. 
 
The Steps are as follows:
&nb...read more
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Q3. Left View Of Binary Tree
Given a binary tree. Print the Left View of the Tree.
Example :
If the input tree is as depicted in the picture: 
The Left View of the tree will be:  2 35 2 
Input format :
...read more
Ans. Recursive Approach
This problem can be solved through recursion.We will maintain max_level variable which will keep track of maxLevel and will pass current level in recursion as argument. Whenever we see a node whose current level is more than maxLevel then we will print that node as that will be first node for that current level. Also update maxLevel with current level.
Space Complexity: O(n)Explanation:
O(N), where ‘N’...read more
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Round duration - 30 minutes
Round difficulty - Medium

basically this round is just same as HR round . they asked me behavioural questions and about my projects , hackathon. the timing is mid noon and interviewer is supportive , it makes first comfortable then start questioning . for this round i suggest be honest , don't just express your qualities but trying to show them by your skills and work.

Q1. Basic HR Questions
Who is your role model?
Why do you want to join the company?
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It was aptitude and coding round basically quesstions were in arrrays and linkedlist

Q1. Oops questions in java
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Round duration - 100 minutes
Round difficulty - Medium

Test started at 04:00 PM sharp and complete the same by 06:00 PM.
The test duration is 100 minutes.
Environment (Amcat) is user friendly and understandable.
Web cam and microphone were also enabled.

Q1. Longest Sub-string with at most K Distinct Characters
You are given string S of length N, and an integer K. Your task is to find the length of the longest substring that contains at most K distinct charact...read more
Ans. Brute Force
• We will generate all the substrings using 2 nested for loops and we will have a ‘CHECK’ function which returns true if the number of distinct character in the substring is less than equal to K otherwise false.
• We will have an ans variable initialize to 0. We will call the ‘CHECK’ function with every substring and if it returns true then
  • ANS = MAX(ANS , CURRENT_SUBSTRING.SIZE())
• To implement the check function w...read more
Answered by CodingNinjas
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Q2. Find Duplicate
You have been given an integer array/list(ARR) of size N which contains numbers from 0 to (N - 2). Each number is present at least once. That is, if N = 5, the array/list constitutes values ...read more
Ans. Space Complexity: Explanation: Time Complexity: Explanation:
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Round duration - 40 minutes
Round difficulty - Hard

This round was conducted on skype platform. I was shared the invitation link one day prior to the interview and also was told the name of my interviewer. I looked at the profile of the interviewer at linked.in and got a better understanding of what kind of person he was and prepared accordingly. The round was scheduled at 3 :00 pm on 5th Nov and I was eagerly waiting for the clock hands to reach 3 o'clock since morning and finally I went in front of him after wearing a white shirt and a black coat over it along with a tie over it.

Q1. Ninja and BInary String
Ninja is given a binary string ‘S’ of size ‘N’ by his friend, the task is to check if the binary string ‘S’ can be sorted in decreasing order by removing any number of the non-adjac...read more
Ans. Greedy
The idea here is to use the fact that while traversing from the end if we encounter 2 consecutive 1s then we can sort the string in decreasing order if and only if after the index which we have found 2 consecutive 1s we have-
• 0-1,1-0 adjacent pair characters- In this case, we can sort the string in decreasing order by removing 0’s from the string as they are not adjacent to each other. For example “1101011” we fin...read more
Answered by CodingNinjas
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Q2. Split the String
You are given a string ‘str’ of ‘N’ lowercase alphabets. Your task is to check whether it is possible to split the given string into three non-empty substrings such that one of them is a ...read more
Ans. Brute-force
The idea here is to check all possible ways to divide a string into 3 substrings and check if there is a string that is a substring of the other two parts. We can divide a string into 3 non-empty substrings:
• A non-empty prefix
• A non-empty suffix
• And a non-empty middle string that is between the ending point of the 1st string and starting point of the 2nd string.
 
Algorithm:
 
• Run a loop from i = 1 to ‘N’...read more
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Round duration - 40 minutes
Round difficulty - Easy

This round was scheduled on 15th Nov, almost after 10 days of the previous technical round. I got the confirmation of passing the previous round on 11th Nov and was asked to appear in this final round which was scheduled on 15th Nov at 11:00 am in the morning and it was going to be an HR round which probably was my favourite among all the other rounds. I prepared for by reading interview experiences available at coding ninjas and geeksforgeeks.

Q1. Basic Puzzles
This puzzle usually seems like a tough one to answer, but solving it once makes one realize that the procedure was actually simple. If the candidate pulls out 2 red balls, he replaces them wit...read more
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Round duration - 120 minutes
Round difficulty - Easy

It consisted of 3 coding questions which were purely based on Data Structures and Algorithms.

Question 1 - Find the length of the longest switching sub-array. An array is called switching if all numbers in even positions are equal and all numbers in odd positions are equal. 


Question 2 - It was a long passage question on Dynamic Programming but the solution was really easy.

Question 3 - Given a string S consisting of N lowercase letters, return the minimum number of letters that must be deleted to obtain a word in which every letter occurs a unique number of times. Ex - "aaaabbbb" should return 1, as when we delete 1 a or 1 b , a and b will have different frequencies.


The major point to note in the coding round was that they did not have any time or space limit, so brute force solutions were also accepted. 
The result of my test was declared just as the test ended and I scored a 100%, but they took a long time to release the final shortlist. There was a gap of about a week between the test and interviews.

Q1. Find the length of the longest switching sub-array. An array is called switching if all numbers in even positions are equal and all numbers in odd positions are equal.
You are given an array 'ARR'...read more
Ans. 
It's like a sliding window problem.
We keep track of even and odd equality with 2 variables, even and odd.
Whenever we come across a unmet condition, like index even but not equal with even variable and same goes for odd, we first
Record the length till now in max_len.
Reset start to i-1 as this is need incase of all elements equal.
Reset even and odd according to current index i to arr[i] and arr[i-1] respectively.
Answered by CodingNinjas
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Q2. Chips at Casino
Given two integer N and K representing number of chips a person has and the number of chips he can use at max at a time, return the minimum number of rounds that are necessary for John to le...read more
Ans. 
It was a dynamic programming question but I was able to solve it with recursion as well.
The approach was simply, that if he wins then he gets 2C chips back. that means 1 turn is used to deploy half the chips he had. while in the other case he just loses a chip and same number of turns are restored.
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Q3. Given a string S consisting of N lowercase letters, return the minimum number of letters that must be deleted to obtain a word in which every letter occurs a unique number of times.For Ex - "aaaabbbb" shou...read more
Ans. Brute Force
As we are only allowed to delete the character, thus the resulting string after deletion of some character would be the subsequence of the string. So, we have to find such a subsequence which has the unique frequency of each character. 
 
Initialise a variable ‘ans’ that will store the minimum number of characters that are needed to remove from the string. Create all the subsequences of the string an...read more
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Round duration - 40 minutes
Round difficulty - Easy

Amex came for two profiles - Tech Role and Analyst, 19 and 23 people respectively were shortlisted for the interviews. Fortunately, I was shortlisted for both the roles. I was asked basic question of C++ and it was majorly an HR Round

Round duration - 20 minutes
Round difficulty - Easy

It was a fairly simple round conssting of 5 - 6 questions related to coding, puzzles and me.

What are your interests? 
What projects have you done and your field of interest?

Q1. Q1. How many stacks are used to implement a queue.
Ans. 
Just the answer which is 2.
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Q2. Q2. What is the difference between a reference and a pointer? Explain with an example.
Ans. 
Reference - No memory is allocated and it is just an alias of the same memory location
Pointer - New memory location is created which stores the address of the location it is pointing to.
Ex -
int& a = b (reference)
int* a = &b (pointer)
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Q3. There is a bulb in a room, you are outside the room and there are 3 switches, what is the minimum number of times you need to open the door to know to which switch the bulb belongs
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Q4. You are given a number if the number is positive, then if n is divisible by 3, print “GO” if n is divisible by 5, print “SLEEP” , if n is divisible by both 3 and 5, print “RETIRE”. If the number equals 0, ...read more
Ans. 
The question explains everything. Just need to use try catch blocks for exception handling
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Round duration - 50 minutes
Round difficulty - Easy

This round was purely technical
No introduction was done, straight to the point

My preference was the Tech Role, so as I was selected in this, I never had to give interviews for the Analyst role. In total 5 people were selected in the Analyst profile and 4 in the Tech profile.

In the end, I was offered a 6 months internship at Amex.

Q1. Given a linked list of characters, tell if it is a palindrome linked list or not.
You are given a singly Linked List of integers. Your task is to return true if the given singly linked list is a palindrome...read more
Ans. 
I gave the two pointer approach. Then he said what if we are provided with the length of the list. I said that we will move forward in the list till n/2 nodes and then the same approach as above. Then he said what if we had to do it with a stack. I said we will add elements into the stack till n/2 nodes and then start popping elements while simultaneously traversing the linked list from the (n/2+1)th node till n if the...read more
Answered by CodingNinjas
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Q2. You are given a student table and a course table with primary keys -> roll number and course_id in each respectively. Since we know that a student can enroll in many courses and a course can be taken by ma...read more
Ans. 
We will create a third table that will store only two columns which are the Primary Keys of both the tables and they together can uniquely identify records in both the tables.

I thought of it but did not reach the solution at once, it took me 3 – 4 attempts for it but he didn’t tell me anything, and finally, I got to the solution.
Answered by CodingNinjas
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