20+ Athenahealth Technology Software Developer Interview Questions and Answers

Find the sum of the subarray with the maximum sum among all subarrays in a given array.

• Iterate through the array and keep track of the maximum sum subarray seen so far.

• Use Kadane's algorithm to efficiently find the maximum subarray sum.

• Consider the case where all elements in the array are negative.

• Handle the case where the array contains only one element.

Generate a pattern with outer rectangle filled with number 'N' and decreasing consecutively inward.

• Start by filling the outermost rectangle with the number 'N'.

• Decrease the numbers consecutively as you move inward towards the center.

• Continue this pattern until you reach the center of the rectangle.

Find the maximum number of head-side up coins by flipping a continuous segment of coins.

• Iterate through the array and calculate the maximum number of head-side up coins without flipping.

• Iterate through the array and calculate the maximum number of head-side up coins after flipping a continuous segment.

• Compare the results from the above two steps to find the maximum number of head-side up coins obtainable.

Find the smallest positive integer missing from an array of integers.

• Iterate through the array and mark positive integers as visited by changing the sign of the corresponding index.

• After marking, iterate again to find the first positive integer with a positive value, which will be the smallest missing positive integer.

• Handle edge cases like all negative numbers, duplicates, and missing 1 separately.

Find the kth missing element in a sequence of integers.

• Iterate through the sequence to find missing elements.

• Keep track of the count of missing elements found.

• Return the kth missing element once count reaches k.

The task is to determine if a given 9x9 Sudoku puzzle can be solved.

• Check if each row, column, and 3x3 subgrid contains all numbers from 1 to 9 without repetition.

• Iterate through each empty cell and try filling it with a valid number, then recursively check if the puzzle can be solved.

• If all empty cells are filled without violating Sudoku rules, output 'yes'; otherwise, output 'no'.

Implement the Heap sort algorithm to arrange an array in non-decreasing order.

• Implement the Heap sort algorithm to sort the given array in non-decreasing order

• Use a max heap to sort the array in non-decreasing order

• Time complexity of Heap sort is O(n log n)

Reverse a given string containing alphabets, numbers, and special characters.

• Iterate through the string from the end to the beginning and append each character to a new string.

• Use built-in functions like reverse() or StringBuilder in languages like Python or Java for efficient reversal.

• Handle special characters and numbers along with alphabets while reversing the string.

• Ensure to consider the constraints provided in the problem statement.

• Test the solution with different test ...read more

Yes, the binary array sorting problem can be solved in linear time and constant space using a single traversal.

• Use two pointers approach to swap 0s to the left and 1s to the right.

• Maintain two pointers, one for 0s and one for 1s, and swap elements accordingly.

• Example: Input: [1, 0, 1, 0, 1], Output: [0, 0, 1, 1, 1]

The N Queens Problem involves finding all possible placements of N queens on an N x N chessboard without threatening each other.

• Use backtracking algorithm to explore all possible configurations.

• Keep track of rows, columns, and diagonals to ensure queens do not threaten each other.

• Generate valid configurations recursively and backtrack when a solution is not possible.

Implement a function to find K largest elements in an unsorted array in non-decreasing order.

• Create a min heap of size K and insert the first K elements of the array

• For each remaining element, if it is larger than the root of the heap, replace the root with the element and heapify

• Finally, the heap will contain the K largest elements in non-decreasing order

Find the smallest distance between two words in a document for multiple queries.

• Iterate through the document to find the indices of the given words in the document array.

• Calculate the distance between the two indices for each query.

• Return the smallest distance or 'N' if a word from the query is not present in the document.

Detect if a singly linked list forms a cycle by checking if a node's next points back to a previous node.

• Traverse the linked list using two pointers, one moving at double the speed of the other

• If the two pointers meet at any point, there is a cycle in the linked list

• If one of the pointers reaches the end of the list (null), there is no cycle

The task is to implement a function that returns the level order traversal of a binary tree given in level order.

• Create a queue to store nodes for level order traversal

• Start with the root node and enqueue it

• While the queue is not empty, dequeue a node, print its value, and enqueue its children

• Repeat until all nodes are traversed

Given a sorted N * N matrix, find the position of a target integer 'X'.

• Start from the top-right corner of the matrix and compare the target with the element at that position.

• Based on the comparison, move left or down in the matrix to narrow down the search.

• Repeat the process until the target is found or the search goes out of bounds.

• Return the position of the target if found, else return {-1, -1}.

The task is to find the next greater element for each element in an array to its right, if no greater element exists, return -1.

• Iterate through the array from right to left and use a stack to keep track of elements.

• Pop elements from the stack until a greater element is found or the stack is empty.

• Store the next greater element for each element in the output array.

Develop a function to remove all instances of a given character from a string.

• Iterate through the string and build a new string excluding the specified character.

• Use a StringBuilder or similar data structure for efficient string manipulation.

• Handle edge cases like empty string or character not found in the input string.

• Ensure the function completes within the given time constraint.

Print a triangle pattern of numbers based on a given number 'N'.

• Iterate through each row and column to determine the numbers to print

• Use a combination of spaces and numbers to align the pattern correctly

• Increment the numbers in each row based on the row number

Convert a binary tree into its mirror tree by interchanging left and right children of non-leaf nodes.

• Traverse the tree in postorder fashion and swap the left and right children of each node.

• Use recursion to solve the problem efficiently.

• Modify the binary tree in place without creating a new tree.

Check if it is possible to form a non-degenerate triangle using the sides provided in the array.

• Check if the sum of any two sides is greater than the third side for all combinations.

• If any such combination exists, return true; otherwise, return false.

• Handle multiple test cases as per the constraints provided.

Pirates follow a specific ranking system to divide 100 gold coins among themselves.

• Pirate 1 proposes a division of coins.

• All pirates, including the proposer, vote on the proposal.

• If majority agree, the coins are divided as proposed. If not, the proposer is thrown overboard and Pirate 2 makes a new proposal.

• This process continues until a majority agree on a proposal.

• Pirates are greedy and will always vote to throw someone overboard if they can get more coins in the next round.

Hash Table is better for fast lookups and insertions, while B Tree is better for range queries and ordered traversal.

• Use Hash Table for fast lookups and insertions with O(1) average time complexity.

• Use B Tree for range queries and ordered traversal with O(log n) time complexity.

• Consider the size of the dataset and the specific operations needed to determine the best data structure.

The minimum number of planes required to go around the world is one.

• One plane can fly around the world without needing to stop.

• The plane can refuel mid-air or carry enough fuel for the entire journey.

• Examples: Non-stop flights like the Boeing 787 Dreamliner or Airbus A350 can circumnavigate the globe with one plane.

BST is a binary tree structure where each node has at most two children, while Tries are tree structures used for storing strings.

• BST is used for searching, inserting, and deleting elements in a sorted manner.

• Tries are used for storing and searching strings efficiently.

• BST has a hierarchical structure with left and right child nodes.

• Tries have nodes representing characters, forming a tree-like structure for strings.

• Example: BST can be used to store numbers in sorted order, wh...read more

Indexing in databases is a technique used to improve the speed of data retrieval by creating a data structure that allows for quick lookups.

• Indexes are created on specific columns in a database table to speed up queries that search for data in those columns.

• Indexes work similar to the index of a book, allowing the database to quickly locate the desired data without having to scan the entire table.

• Examples of indexes include primary keys, unique keys, and composite indexes.

• Wit...read more