Problem 062: Cubic permutations
41063625 (345^3), can be permuted to produce two other cubes:
56623104 (384^3) and
41063625 is the smallest cube which has exactly three permutations of its digits which are also cube.
Find the smallest cube for which exactly five permutations of its digits are cube.
$ # #
$ . .
$ . .
$ . .
# ... #
v _v#!:p/g42\+ <
>5 28p 78*9*3-: 24p 68*: 25p*:26p >1-:0\:24g%4^
v < v+1 <
>1+:::**:22p 0\v v\-1 <>20p0>:3*:24g%4+\24 g/g:|
$ v+55:<>\1>9*\:|: @$$$.g/g42\+4%g42:+1$ <
>%\:#^|#/+55\$<+ > 3*:2+:24g%4+\24g/g1+:28g-!|
>$ #\>#<>\# :#+_^ >*::2v vp/g42\+4%g42:+2\<
Only after at least sixty-two mathematical programs in befunge you will truly appreciate a hashtable.
For real, everything would be so much better if I could retrieve this stuff in
My approach is pretty straight-forward. We calculate an permutation-insensitive hash. Then store them together with the times it appeared in a hashmap (I mean a list -.-). Now we just go through all the cubes until a single hash appeared five times. In C# with a Dictionary this takes around 10ms.
|Interpreter steps:||952 323 293|
|Execution time (BefunExec):||6min 3s (2.62 MHz)|
|Program size:||505 x 58|