Meta Software Developer interview questions

1) Calculate the square root of a double 2) Given n intervals [si, fi], find the maximum number of overlapping intervals. 3) Print all the paths from root to every leaf in a binary tree. 4) Print the sum of all the numbers at every vertical level in a binary tree 5) Given a set of n jobs with [start time, end time, cost] find a subset so that no 2 jobs overlap and the cost is maximum ? 6) Given 1 trillion messages on fb and each message has at max 10 words, how do you build the index table and how many machines do you need on the cluster to store the index table ?