! Copyright (c) 2009 Guillaume Nargeot.
! See http://factorcode.org/license.txt for BSD license.
-USING: kernel math math.primes.factors math.ranges
-project-euler.common sequences ;
+USING: math.primes.factors project-euler.common ranges sequences ;
IN: project-euler.072
! http://projecteuler.net/index.php?section=problems&id=072
! The answer can be found by adding totient(n) for 2 ≤ n ≤ 1e6
: euler072 ( -- answer )
- 2 1000000 [a,b] [ totient ] [ + ] map-reduce ;
+ 2 1000000 [a..b] [ totient ] map-sum ;
! [ euler072 ] 100 ave-time
! 5274 ms ave run time - 102.7 SD (100 trials)