HashedIn by Deloitte Interview Questions, Process, and Tips for Freshers

Sort an array of 0s, 1s, 2s in linear time.

• Use three pointers to keep track of the positions of 0s, 1s, and 2s.

• Traverse the array once and swap elements based on their values.

• The final array will have 0s, 1s, and 2s grouped together in that order.

Finding the Kth smallest element in an array.

• Sort the array and return the Kth element.

• Use a min heap to find the Kth smallest element.

• Use quickselect algorithm to find the Kth smallest element.

• Divide and conquer approach using binary search.

• Use selection algorithm to find the Kth smallest element.

Designing APIs and finding second largest value in SQL query.

• For API design, consider RESTful principles and use clear and concise naming conventions.

• For finding second largest value in SQL, use ORDER BY and LIMIT clauses.

• Consider edge cases such as duplicates and null values.

• Test thoroughly to ensure correct functionality.

Check if there exists a pair of numbers in the array that add up to a given sum.

• Iterate through the array and for each element, check if the difference between the sum and the element exists in the array using a hash table.

• Alternatively, sort the array and use two pointers to traverse from both ends towards the middle, adjusting the pointers based on the sum of the current pair.