Directi Software Engineer Interview Questions, Process, and Tips

Sorting an array of 0, 1 and 2 can be done in O(n) using two pointers.

• Use two pointers, one for 0 and one for 2, and a current pointer to traverse the array

• If the current pointer encounters a 0, swap it with the 0 pointer and move both pointers to the right

• If the current pointer encounters a 2, swap it with the 2 pointer and move the 2 pointer to the left

• Repeat until the current pointer meets the 2 pointer

Algorithm to find if a number is present in a sorted n x n matrix with linear time complexity.

• Start with the top right element

• Compare the element with x

• If equal, return its position

• If e < x, move down (if out of bounds, return false)

• If e > x, move left (if out of bounds, return false)

• Repeat till element is found or returned false

The problem is to find non-empty subsets of a given set of integers whose sum is zero.

• The problem is a special case of the knapsack problem and is known to be NP-Complete.

• A brute-force approach would involve generating all subsets and checking their sums.

• The brute-force approach has an exponential time complexity.

• There is no known polynomial time solution for this problem.

Data structure with O(1) insert, delete, and find min without creating new structures

• Use two stacks, one for actual data and one for minimum values

• When inserting, push the value onto the data stack and push the minimum of the new value and the top of the minimum stack onto the minimum stack

• When deleting, pop from both stacks

• When finding the minimum, return the top of the minimum stack

The glasses are stacked like a pyramid on a table. Each glass can hold a certain amount of water, and the overflow is distributed equally to the glasses below.

• The glasses form a pyramid shape, with the topmost glass being the first level and each subsequent level having one more glass than the previous level.

• The amount of water held by each glass can be calculated by dividing the total amount of water by the number of ...read more

Divide a rectangle of M x N into smaller rectangles of M1 x N1 to minimize wastage.

• Start by dividing the rectangle horizontally or vertically based on the dimensions of the smaller rectangles.

• Continue dividing each resulting sub-rectangle until no further division is possible.

• Consider the dimensions of the smaller rectangles and the remaining space to minimize wastage.

• Keep track of the divisions made to reconstruct the

The number of 'BB' occurrences at the Nth iteration of the transformation sequence.

• At each iteration, A gets transformed to AB and B gets transformed to BA.

• To find the number of 'BB' occurrences at the Nth iteration, we need to count the number of 'BB' substrings in the transformed string.

• The transformation sequence follows a pattern: AB, ABA, ABAAB, ABAABABA, ...

• The number of 'BB' occurrences doubles with each iterati...read more