I had four technical interviews, one interview on my PhD projects, and lunch with an employee.

Each interview took 45 minutes.

All interviews were conducted consecutively: as soon as one interview finished, the next interviewer came in and began another.

1. Write two functions: (A) Given an n by n grid, add a land at location (x,y). (B) Find the number of islands, where an island is a group of adjacent lands.

2. (A) Given a set of numbers, find a subset of the numbers whose sum is equal to the sum of the complement set. (B) Given a sequence of numbers, find a subsequence whose sum is the largest.

3. Given a pre-order and an in-order traversal of a tree, reconstruct the tree.

4. Given a 32-bit sequence, find the most significant bit.