Consider program p, which runs on a 4 ghz machine m in 200 seconds. consider an optimization to p that replaces all instances of multiplying a value by 4 (mult x, x,4) with two instructions that set x to x x twice (add x, x; add x, x). assume that every multiply instruction takes 6 cycles to execute, and every add instruction takes just 1 cycle. after recompiling, the program now runs in 150 seconds on machine m. determine how many multiplies were replaced by this optimization.

Suppose you are an ad-serving company and you maintain a log of cookie data for ads you serve to the web pages for a particular vendor (say amazon). a. how can you use this data to determine which are the best ads? b. how can you use this data to determine which are the best ad formats? c. how could you records of past ads and ad clicks to determine which ads to send to a given ip address? d. how could you use this data to determine how well the technique you used in your answer to part c was working? e. how could you use this data to determine that a given ip address is used by more than one person? f. how does having this data give you a competitive advantage vis-à-vis other ad-serving companies?