1 ! Copyright (c) 2008 Aaron Schaefer.
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: kernel math.functions math.ranges project-euler.common sequences ;
6 ! http://projecteuler.net/index.php?section=problems&id=56
11 ! A googol (10^100) is a massive number: one followed by one-hundred zeros;
12 ! 100^100 is almost unimaginably large: one followed by two-hundred zeros.
13 ! Despite their size, the sum of the digits in each number is only 1.
15 ! Considering natural numbers of the form, a^b, where a, b < 100, what is the
16 ! maximum digital sum?
22 ! Through analysis, you only need to check when a and b > 90
24 : euler056 ( -- answer )
25 90 100 [a,b) dup cartesian-product
26 [ first2 ^ number>digits sum ] map supremum ;
28 ! [ euler056 ] 100 ave-time
29 ! 22 ms ave run time - 2.13 SD (100 trials)