Adobe (4 rounds)

F2F-1
You have a grid of size M cross N with negative and positive numbers with row and column wise sorted order (assume increasing order sorting). Find the count of negative numbers in the grid
Given a sorted array of positive and negative numbers find a pair of numbers whose sum is x.
Next level is find the pair with sum = x in Binary Search Tree.

F2F-2
If numbers are represented in linked list. Ex - 931 as 9->3->1->NULL, then add two numbers and get the result linked list in Recursive code.
You have a stream of numbers coming at you. Keep track of the Nth largest number in the stream. Discuss the data structure for this situation and code.
You are given an array containing 0’s 1’s and 2’s what is the best way to sort it.

F2F-3
Given that a linked list has a loop in it, detect the start of loop. After that prove either mathematically or by providing proper test cases that the solution to the above problem will work in all possible cases.
Reverse all words of a string.

F2F-4
Allocate memory for a N dimensional matrix in C using malloc and handle all the memory leaks and Crashes that can occur.
There is a property P which belongs to A. A has n friends Bi (1 <= i <=n). each of Bi has n friends Cij (1 <= i,j <=n). The property can be accessed by A , all friends of A, and All friends of friends of A that is A , all the B's, all C’s. Given the identity of a person find if he has access to P or not. Think of the data structure that will result in the fastest solution.