Athenahealth Technology Software Developer Interview Questions, Process, and Tips

Q1. Concepts of OOPS
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Round duration - 90 minutes
Round difficulty - Medium

The online test was scheduled on 10:00 AM. Total 304 students were eligible who appeared for the test. 93 students were shortlisted in this round. MCQs were asked and two coding question

MCQs were of medium to hard level.
OOPS(2 Question)
DBMS(2 questions)
Networking(2 Questions)
Operating System(2 Questions),
Aptitude(2 Questions)

Q1. 
Maximum Subarray Sum Problem Statement
Given an array arr of length N consisting of integers, find the sum of the subarray (including empty subarray) with the maximum sum among all subarrays.
Explanation...read more
Ans. 
A subarray is a contiguous segment of an array. In other words, a subarray can be formed by removing 0 or more integers from the beginning, and 0 or more integers from the end of an array. I used Kadane's algorithm to solve it optimally. 
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Q2. 
Flipping Coins Problem
Gary has N coins placed in a straight line. Some coins have their head side up, and others have the tail side up.
Convention:
1 denotes the HEAD side is up. 
0 denotes the TAIL sid...read more
Ans. Brute force
1. The idea is to check every subarray.
2. We can count the number of heads and number tails in every subarray and then calculate the maximum number of heads side up we can obtain if we flip that particular subarray.
3. We also keep a count of the final start index and final end index that will give us the number of heads side up we can obtain later.
Space Complexity: O(1)Explanation:
O(1).
 
In the worst case, only ...read more
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Round duration - 60 minutes
Round difficulty - Medium

It was technical interview round, which was purely based on coding followed by 1 SQL query. Duration of round was of 1 hour from 10 AM-11AM. Interviewer asked me 2 Coding questions one to solve and run on Hackerrank codepair platform and for another one she asked only my approach to solve problem. In the remaining last 10 minutes interviewer asked me 1 SQL query on JOIN. Total 28 students were shortlisted in this round.

Q1. 
First Missing Positive Problem Statement
You are provided with an integer array ARR of length 'N'. Your objective is to determine the first missing positive integer using linear time and constant space. T...read more
Ans. 
I gave him the optimized solution.
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Q2. 
Problem: kth Missing Element in a Sequence
Given a strictly increasing sequence of integers VEC, identify the Kth missing contiguous integer element that is not present in the sequence, starting from the ...read more
Ans. 
I told the solving approach by using max heap in O(NlogK) time complexity.
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Round duration - 60 minutes
Round difficulty - Medium

This was a test round where 10 aptitude based questions were to be solved in 60 minutes

Q1. You have 5 pirates and 100 gold coins. The challenge is to determine how the pirates will divide the coins among themselves based on their ranking and the rules they follow.
Ans. 
The answer is 98. 
A uses the facts below to get 98 : 
Consider the situation when A, B, and C die, only D and E are left. E knows that he will not get anything (D is senior and will make a distribution of (100, 0). So E would be fine with anything greater than 0.
Consider the situation when A and B die, C, D, and E are left. D knows that he will not get anything (C will make a distribution of (99, 0, 1)and E wi...read more
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Round duration - 60 minutes
Round difficulty - Medium

They took us to the lab for this on and we were each given a paper with a program on it. It was all mixed as in each person got a different paper, You have around an hour to finish coding. after which you have to explain your code. They also gave wrong or incorrect inputs and see how your code handles these exceptions.

Q1. 
Reverse the String Problem Statement
You are given a string STR which contains alphabets, numbers, and special characters. Your task is to reverse the string.
Example:
Input:
STR = "abcde"
Output:
"e...read more
Ans. 
This can be done by iterative swapping using two pointers. The first pointer points to the beginning of the string, whereas the second pointer points to the end. Both pointers keep swapping their elements and go towards each other. Essentially, the algorithm simulates the rotation of a string with respect to its midpoint.
Time Complexity : O(n)
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Q2. 
K Largest Elements Problem Statement
Given an unsorted array containing 'N' integers, you are required to find 'K' largest elements from the array and return them in non-decreasing order.
Input:
The fir...read more
Ans. 
To solve the question using a max heap, make a max heap of all the elements of the list. Run a loop for k-1 times and remove the top element of the heap. After running the loop, the element at top will be the kth largest element, return that. Time Complexity : O(n + klogn)
The question can also be solved using a min heap. 
Approach:
1. Create a min heap class with a capacity of k
2. When the heap reaches capacity ejec...read more
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Q3. 
Remove Character from String Problem Statement
Given a string str and a character 'X', develop a function to eliminate all instances of 'X' from str and return the resulting string.
Input:
The first lin...read more
Ans. Iterative Solution
• We create an empty string that will store our final result. We will return it at the end.
• We iterate from 0 to the length of the string. Say, our loop variable is i. We can then access the ith character as input[i]
• If the ith character equals the character c i.e input[i] == c, then we skip this character and do nothing.
• Else we need to append the character to the output string.
• We finally return the outpu...read more
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Q4. 
Triangle of Numbers Pattern
Ninja is tasked with printing a triangle pattern based on a given number 'N' for any test case.
Example:
Input:
N = 4
Output:
   1
  232
 34545
4567654
Explanation:
The pat...read more
Ans. 
printPattern(int n)
{
// Outer loop to handle number of rows n in this case
for (int i = 0; i < n; i++) {
// Inner loop to handle number of columns values changing acc. to outer loop
for (int j = 0; j <= i; j++) {
Print stars (*)
}

Print new line
}
}
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Round duration - 60 minutes
Round difficulty - Easy

Compared to the other round this is more tech oriented. Lot more tech questions. It is of normal difficulty and is not that hard to clear, you only need to know the basics.
Very basic of Data Structure and Oracle knowledge enough. Lots of simple questions from data structures(insert into heaps etc). They did not ask to write code for DS, but rather to explain the logic through diagrams. For some complicated question, they expect how much you brainstorm ideas in solving

Q1. 
Convert Binary Tree to Mirror Tree
Convert a given binary tree into its mirror tree, where the left and right children of all non-leaf nodes are interchanged.
Input:
An integer ‘T’ denoting the number o...read more
Ans. 
This can be solved using recursion. 
Steps :
(1) Call Mirror for left-subtree i.e., Mirror(left-subtree)
(2) Call Mirror for right-subtree i.e., Mirror(right-subtree)
(3) Swap left and right subtrees.
temp = left->subtree
left->subtree = right->subtree
right->subtree = temp

Worst-case Time complexity is O(n) 
Auxiliary space complexity : O(h) where h is the height of the tree.
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Q2. 
Heap Sort Problem Statement
Given an array ARR consisting of N integers, your task is to use the Heap sort algorithm to arrange the array in non-decreasing order.
Input:
The first line of the input cont...read more
Ans. 
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to selection sort where we first find the minimum element and place the minimum element at the beginning. We repeat the same process for the remaining elements.

Algorithm :

HeapSort(arr) 
BuildMaxHeap(arr) 
for i = length(arr) to 2 
swap arr[1] with arr[i] 
heap_size[arr] = heap_size[arr] ? 1 
MaxHeapi...read more
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Q3. What is indexing in the context of databases?
Ans. 
Indexing is a data structure technique used to efficiently retrieve records from the database files. It helps optimize the performance of a database by minimizing the number of disk accesses required when a query is processed.
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Q4. Which data structure is better for your use case: a B Tree or a Hash Table?
Ans. 
1. B+ tree is costly to maintain since it needs to be updated after every insertion and deletion.
2. Hash based indexing is efficient in equity queries whereas B+ trees are efficient in range queries.
3. Efficiency of hash based index is low in case of large no. of repeated key values because of hash collision problems.
4. Hash index is not efficient in sorting.
5. Hash index is effective in insertion and deletion whereas
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Round duration - 30 minutes
Round difficulty - Easy

This round lasted for around 30 minutes. It more of a character analysis round with a lot of HR type questions.

Round duration - 60 minutes
Round difficulty - Easy

10 Aptitude questions with difficulty level hard were asked in this test.

Q1. What is the minimum number of planes required to go around the world?
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Round duration - 60 minutes
Round difficulty - Easy

Technical Interview round with questions based on data structures and algorithms. Questions about previous projects done and my roles on it and my leadership capabilities. Few technical questions from Threads and multi-processing.

Q1. 
Search in a Row-wise and Column-wise Sorted Matrix Problem Statement
You are given an N * N matrix of integers where each row and each column is sorted in increasing order. Your task is to find the positi...read more
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Q2. 
Rectangular Numbers Problem Statement
Ninja has a number 'N'. Your task is to generate a pattern where the outer rectangle is filled with the number 'N', and as you move inward, the numbers decrease conse...read more
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Round duration - 60 minutes
Round difficulty - Medium

DSA based questions were asked in this round. Questions on implementation of Linux directory structure were also asked.

Q1. 
Binary Array Sorting Problem Statement
You are provided with a binary array, i.e., an array containing only 0s and 1s. Your task is to sort this binary array and return it after sorting.
Input:
 The fir...read more
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Q2. 
Next Greater Element Problem Statement
You are given an array arr of length N. For each element in the array, find the next greater element (NGE) that appears to the right. If there is no such greater ele...read more
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Q3. What is the difference between Binary Search Trees (BST) and Tries?
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Round duration - 60 minutes
Round difficulty - Easy

This was a technical round. Questions about previous projects and current one were asked. I was also asked about aptitude problems from the first round and how I understood and approached towards solution?

Q1. 
N Queens Problem
Given an integer N, find all possible placements of N queens on an N x N chessboard such that no two queens threaten each other.
Explanation:
A queen can attack another queen if they ar...read more
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Q2. 
Form a Triangle Problem Statement
You are provided with an integer array/list ARR of length N. Your task is to determine if it is possible to construct at least one non-degenerate triangle using the value...read more
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Round duration - 30 minutes
Round difficulty - Easy

Behavioral questions and team skills were discussed in this round.