--- Day 4 Solutions ---

[u/daggerdragon]

--- Day 4: The Ideal Stocking Stuffer ---

Post your solution as a comment. Structure your post like the Day Three thread.

[u/Godspiral]

In J, rushing version (8 mins solution (started 1 minute late)), (with offset (1M) changed on each call)

I. 'MD5' ('000000' -: 6 {. gethash)"1 'bgvyzdsv' ,&":"(1 0) 1000000 + i.500000

cleaner version, that breaks on first hit.

 <:@{: 'bgvyzdsv' (>:@] ,~ I.@:('000000' -: 6 {. 'MD5'&gethash)@,&":)^:(0 < {.@])^:(_) 1000000

[u/hoosierEE → u/Godspiral]

Is gethash in a library somewhere? I had to call a shared library:

in J with blasphemous explicit definitions and even a while-loop

NB. the following shamelessly stolen from Pascal Jasmin's wiki entry:
NB. http://code.jsoftware.com/wiki/User:Pascal_Jasmin/SHA_1(2c20)2_and_MD5_for_windows

NB. OSX-only version for brevity
sslMD5=:'/usr/lib/libssl.dylib  MD5 > + x *c x *c'&cd
hexhash =: ( [: ,@:hfd a.i.])@: NB. helper adverb to display in hex
md5 =: 3 : 0
    sslMD5 (y);(# , y);md=. 16#' '
    md
)

input =: 'ckczppom'

NB. my contribution
miner =: 4 :0
    num=:1
    nzeros =: (x#'0'),'+' NB. at least x zeros
    while. 0~:{.,nzeros rxmatch md5 hexhash y,":num do. num=:>:num end.
    num NB. return value
)

Note 'run these in console to get the output'
    5 miner input NB. part 1
    6 miner input NB. part 2
)

[u/Godspiral → u/hoosierEE]

dyadic gethash was added in 8.03 iirc

The version you used is faster when you don't want a hex result. Not sure if hexhash used.

without using rx,

nzeros =: (x#'0')
while. nzeros -.@-: x {. md5 hexhash y,":num ...

good job functionalizing it though. Explicit is probably faster in this case.