1 ! Copyright (c) 2008 Aaron Schaefer.
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: hashtables kernel math.functions math.ranges project-euler.common
7 ! http://projecteuler.net/index.php?section=problems&id=29
12 ! Consider all integer combinations of a^b for 2 ≤ a ≤ 5 and 2 ≤ b ≤ 5:
14 ! 2^2 = 4, 2^3 = 8, 2^4 = 16, 2^5 = 32
15 ! 3^2 = 9, 3^3 = 27, 3^4 = 81, 3^5 = 243
16 ! 4^2 = 16, 4^3 = 64, 4^4 = 256, 4^5 = 1024
17 ! 5^2 = 25, 5^3 = 125, 5^4 = 625, 5^5 = 3125
19 ! If they are then placed in numerical order, with any repeats removed, we get
20 ! the following sequence of 15 distinct terms:
22 ! 4, 8, 9, 16, 25, 27, 32, 64, 81, 125, 243, 256, 625, 1024, 3125
24 ! How many distinct terms are in the sequence generated by a^b for 2 ≤ a ≤ 100
31 : euler029 ( -- answer )
32 2 100 [a..b] dup [ ^ ] cartesian-map concat members length ;
34 ! [ euler029 ] 100 ave-time
35 ! 704 ms ave run time - 28.07 SD (100 trials)