APT Research Private Limited Interview Questions and Answers

The task is to determine the lexicographically smallest array that can be obtained by performing at most 'K' swaps of consecutive elements.

• Iterate through the array and swap elements to make the array lexicographically smallest.

• Keep track of the number of swaps made and stop when the limit 'K' is reached.

• Use a sorting algorithm to find the lexicographically smallest array after at most 'K' swaps.

Given an array and a target sum, find pairs of elements that add up to the target sum.

• Iterate through the array and for each element, check if the complement (target sum - current element) exists in a hash set.

• If the complement exists, add the pair to the result list.

• Sort the result list based on the first element of each pair, and then the second element if the first elements are equal.

Find the minimum time required to rot all fresh oranges in a grid.

• Iterate through the grid to find rotten oranges and their adjacent fresh oranges.

• Use BFS or DFS to simulate the rotting process and track the time taken.

• Return the minimum time taken to rot all fresh oranges or -1 if not possible.

Find the K-th largest element in a binary search tree.

• Perform an in-order traversal of the BST to get elements in ascending order

• Return the (N-K)th element from the end of the in-order traversal

• Handle cases where K is out of bounds or no K-th largest element exists

Find the longest common prefix among an array of strings.

• Iterate through the characters of the first string and compare with corresponding characters of other strings.

• Stop when a mismatch is found or when reaching the end of the shortest string.

• Return the prefix found so far as the longest common prefix.

Find the peak element in an array of integers.

• Iterate through the array and check if the current element is greater than its neighbors.

• Handle edge cases where the first or last element can be a peak.

• Return the peak element found.

Evaluate division problem statement with given fractions and values to calculate the value of a given fraction.

• Use a graph data structure to represent the fractions and values.

• Perform depth-first search (DFS) to find the value of the given fraction.

• Multiply the values of the fractions along the path from numerator to denominator to get the final result.

To make a fair game out of an unfair die showing heads with probability p, we can introduce a penalty for rolling heads.

• Introduce a penalty for rolling heads, such as losing a point or skipping a turn.

• Adjust the game rules to account for the unfair die, ensuring that the penalty balances out the advantage of rolling heads.

• Consider incorporating strategic elements or decision-making to mitigate the impact of the unfair die on the game's fairness.