Big Data Studies

2. Questions about MapReduce framework.

a. Facebook updates the common friends of you and response to hundreds of millions ofrequests every day. The friendship information is stored as a pair (Person, [List of friends]) for every user in the social network. Write a MapReduce program to return a dictionary of common friends ofthe form ((User i, User j), [List of Common friends of i and j]) for all pairs of i and j who are friends. The order of i and j you returned should be the same as the lexico graphical order of their names. You need to give the pseudocode of a main function, and both Map() and Reduce()function. Specify the key/value pair and their semantics (what are they referring to?)

b. Top10 keywords. Search engine companies like Google maintains hot webpages in a set R for keyword search. Each record r from set R is an article, stored as a sequence of keywords. Write a MapReduce programto reportthe top 10 most frequent keywords appeared in the webpages in R. (hint: you may need two rounds of MR process). Give the pseudocode of your MR program.