38 lines
1.1 KiB
Factor
38 lines
1.1 KiB
Factor
! Copyright (c) 2008 Aaron Schaefer.
|
|
! See http://factorcode.org/license.txt for BSD license.
|
|
USING: hashtables kernel math.functions math.ranges project-euler.common
|
|
sequences sets ;
|
|
IN: project-euler.029
|
|
|
|
! http://projecteuler.net/index.php?section=problems&id=29
|
|
|
|
! DESCRIPTION
|
|
! -----------
|
|
|
|
! Consider all integer combinations of a^b for 2 ≤ a ≤ 5 and 2 ≤ b ≤ 5:
|
|
|
|
! 2^2 = 4, 2^3 = 8, 2^4 = 16, 2^5 = 32
|
|
! 3^2 = 9, 3^3 = 27, 3^4 = 81, 3^5 = 243
|
|
! 4^2 = 16, 4^3 = 64, 4^4 = 256, 4^5 = 1024
|
|
! 5^2 = 25, 5^3 = 125, 5^4 = 625, 5^5 = 3125
|
|
|
|
! If they are then placed in numerical order, with any repeats removed, we get
|
|
! the following sequence of 15 distinct terms:
|
|
|
|
! 4, 8, 9, 16, 25, 27, 32, 64, 81, 125, 243, 256, 625, 1024, 3125
|
|
|
|
! How many distinct terms are in the sequence generated by a^b for 2 ≤ a ≤ 100
|
|
! and 2 ≤ b ≤ 100?
|
|
|
|
|
|
! SOLUTION
|
|
! --------
|
|
|
|
: euler029 ( -- answer )
|
|
2 100 [a,b] dup cartesian-product [ first2 ^ ] map prune length ;
|
|
|
|
! [ euler029 ] 100 ave-time
|
|
! 704 ms ave run time - 28.07 SD (100 trials)
|
|
|
|
SOLUTION: euler029
|