10+ Atlassian Software Developer Interview Questions and Answers

Count the number of structurally unique binary trees that can be constructed with given Dragon Balls.

• Use dynamic programming to solve this problem efficiently.

• The number of structurally unique binary trees can be calculated using Catalan numbers.

• For each test case, calculate the number of structurally unique binary trees modulo 10^9 + 7.

• Return the count of unique binary trees for each test case.

Given an encrypted string with repeated substrings represented by counts, find the K'th character of the decrypted string.

• Parse the encrypted string to extract substrings and their counts

• Iterate through the substrings and counts to build the decrypted string

• Track the position in the decrypted string to find the K'th character

Yes, the quick sort algorithm can be enhanced to achieve NlogN complexity in the worst case by using randomized quick sort or median of three pivot selection.

• Use randomized quick sort to randomly select the pivot element, reducing the chances of worst-case scenarios.

• Implement median of three pivot selection to choose a pivot that is closer to the median value, improving partitioning efficiency.

• Consider using dual pivot quick sort for further optimization in certain cases.

• Exam...read more

The Weighted Job Scheduling problem involves maximizing profit by scheduling non-overlapping jobs with given start times, end times, and profits.

• Sort the jobs by end time in ascending order.

• Initialize an array 'dp' to store maximum profit at each job index.

• For each job, find the latest non-overlapping job and update 'dp' with the maximum profit.

• Return the maximum profit from 'dp'.

The goal is to schedule jobs to maximize profit while meeting deadlines. Each job takes one unit of time and only one job can be scheduled at a time.

• Sort the jobs in decreasing order of profit

• Iterate through the sorted jobs and schedule them based on their deadlines

• Keep track of the total profit achieved

• Ensure each job is completed before its deadline

Determine the minimum number of platforms needed at a railway station so that no train has to wait.

• Sort the arrival and departure times arrays in ascending order.

• Use two pointers to iterate through the arrays and keep track of the number of platforms needed.

• Increment the number of platforms needed when a train arrives and decrement it when a train departs.

• Return the maximum number of platforms needed at any point.

• Example: Input: T = 1, N = 3, AT = [900, 940, 950], DT = [910, ...read more

Given a list of correct spellings and a query string, return a list of suggested correct spellings if the query is misspelled.

• Iterate through the dictionary to check for matching prefixes with the query string.

• If a match is found, add the corresponding word to the list of suggestions.

• Return the list of suggestions if the query is misspelled, otherwise return an empty list.

Implement a function to return the spiral order traversal of a binary tree.

• Traverse the binary tree level by level, alternating between left to right and right to left.

• Use a queue to keep track of nodes at each level.

• Append nodes to the result list in the order they are visited.

Low-level languages interact directly with hardware, while high-level languages are more abstract and easier to read/write.

• Low-level languages are closer to machine code and hardware, while high-level languages are closer to human language.

• Low-level languages require more manual memory management and are less portable, while high-level languages have automatic memory management and are more portable.

• Examples of low-level languages include Assembly and C, while examples of hig...read more

Design a file system to calculate total size and find top k collections in size.

• Create a file system class with methods to add files and calculate total size.

• Maintain a data structure to store the collections and their sizes.

• Implement a method to find the top k collections based on size.

• Consider using a priority queue or sorting the collections based on size.

• Handle edge cases like empty collections or invalid input sizes.

The question is asking to find the top k collections.

• Use a sorting algorithm to sort the collections in descending order based on a specific criteria.

• Select the top k collections from the sorted list.

• Return the selected collections as an array of strings.