I saw the pattern in the matrix problem but did not pick up on the BFS solution. Even though I would have solved it, the interviewer prompted me to the BFS solution. In the second problem I used recursion to visit the nodes in order but panicked and did not finish the relinking. In the second interview, I used a minheap to get the Kth largest but I think there is a better solution. I solved the second question with a sliding window in O(n) time for positive numbers only. I couldn't better the On(n^2) when negative numbers are involved.