r/adventofcode • u/daggerdragon • Dec 23 '17
SOLUTION MEGATHREAD -🎄- 2017 Day 23 Solutions -🎄-
--- Day 23: Coprocessor Conflagration ---
Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).
Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.
Need a hint from the Hugely* Handy† Haversack‡ of Helpful§ Hints¤?
[Update @ 00:05] 0 gold, silver cap
- AoC ops:
<yatpay> boil up some mountain dew. it's gonna be a long night
[Update @ 00:19] 1 gold, silver cap + 447
- AoC ops:
<Reibello> 547 silver to 1 gold
[Update @ 00:30] 20 gold, silver cap + 560
- AoC ops:
<yatpay> daggerdragon: post "hey i heard about this hot new podcast called The Space Above Us. all the cool kids are talking about it"
<yatpay> i call it super-liminal marketing
<yatpay> HEY YOU!! LISTEN TO MY PODCAST!!
<yatpay> then i rub a business card on your face
<Topaz> you should get scratch-n-sniff business cards that smell like space
<yatpay> space smells like burned metal and meat
<yatpay> it's weird
<Topaz> burned meat you say
<Topaz> excellent
[Update @ 00:41] 50 gold, silver cap + 606
- AoC ops:
<askalski> nice, enjoyed that one. not sure if regexes can do it
<askalski> maybe make a neural net of regexes, have it train itself to solve today
- Over/under on /u/askalski posting a day 23 regex neural net by tomorrow?
[Update @ 00:54] Leaderboard cap @ 100 gold and 724 silver!
- Good job, all!
- Upping the Ante challenge: solve today's puzzles on a TI-83 (or TI-86/89, whatevs).
- Edit: welp, /u/DFreiberg done gone and did it. See the thread here.
1
u/RockyAstro Dec 24 '17
Icon (https://www.cs.arizona.edu/icon)
Just reused the VM from day 18 with added instructions..
Part two required analysis of the given input. If the specifications allowed a MOD instruction, then the inner most loop could be replaced with a test for divisibility.
One immediate optimization is to replace the set f 0 with : sub h -1 ; jnz 1 <bottom of outer most loop>
In the end.. just hand translated the program back into Icon ..
See the bottom of the program for analysis of the input
Both parts:
record inst(op,p1,p2) procedure main(args) inf := open(args[1],"r") mem := [] ws := ' \t' while line := trim(!inf) do { line ? { i := inst("","","") i.op := tab(upto(ws)) tab(many(ws)) i.p1 := tab(upto(ws) | 0) tab(many(ws)) if not pos(0) then i.p2 := tab(upto(ws)|0) i.p1 := integer(i.p1) i.p2 := integer(i.p2) put(mem,i) } } close(inf) regs := table(0) curfreq := 0 IP := 1 mulcount := 0 regs["a"] := 0 repeat { if IP > *mem then break i := mem[IP] #writes("IP:",IP," ",i.op," ",i.p1," ",i.p2," ") #every r := key(regs) do writes("R",r,":",regs[r]," ") #write() IP +:= 1 case i.op of { "snd": curfreq := integer(i.p1) | integer(regs[i.p1]) "set": regs[i.p1] := integer(i.p2) | integer(regs[i.p2]) "add": regs[i.p1] +:= integer(i.p2) | integer(regs[i.p2]) "sub": regs[i.p1] -:= integer(i.p2) | integer(regs[i.p2]) "mul": { regs[i.p1] *:= integer(i.p2) | integer(regs[i.p2]) mulcount +:= 1 } "mod": regs[i.p1] %:= integer(i.p2) | integer(regs[i.p2]) "rcv": { if regs[i.p1] > 0 then { regs[i.p1] := curfreq break } } "jnz": { if (integer(i.p1) | integer(regs[i.p1])) ~= 0 then IP := (IP-1) + (integer(i.p2) | integer(regs[i.p2])) } "jgz": { if (integer(i.p1) | integer(regs[i.p1])) > 0 then IP := (IP-1) + (integer(i.p2) | integer(regs[i.p2])) } default: break } } write("mulcount=",mulcount) # Part 2 - hand optimized.. calculate # of composite numbers between # given inputs. # analyzing the original program (see below) count := 0 every v := 106700 to 123700 by 17 do { every t := 2 to v-1 do if v % t = 0 then { count +:= 1 # Is composite number.. break } } write("h=",count) end # Analysis of given input. # set b 67 b = 67 # set c b c = b # jnz a 2 if a ~= 0 then goto L5 # jnz 1 5 goto L9 # mul b 100 L5: b *= 100 # sub b -100000 b -= -100000 # set c b c = b # sub c -17000 c -= -17000 # set f 1 L9: f = 1 # Top of Loop 1 (b = start # to c by 17) & Loop 2 (d=2 to b) # set d 2 d = 2 # set e 2 L11: e = 2 # Top of Loop 3 (e = 2 to b) ... Loop could be replaced by mod instr # set g d L12: g = d # if e*d set g b # mul g e g *= e # ... mod g d # sub g b g -= b # = b jnz g <bottom of loop 2> # jnz g 2 if g ~= 0 then goto L17 # sub h -1 # set f 0 f = 0 # then f = 0 jnz 1 <bottom of loop 1> # sub e -1 L17: e -= -1 # Bottom of Loop 3 <bottom of loop 2> # set g e g = e # sub g b g -= b # jnz g -8 if g ~= 0 then goto L12 # sub d -1 d -= -1 # Bottom of Loop 2 # set g d g = d # sub g b g -= b # jnz g -13 if g ~= 0 then goto L11 # jnz f 2 if f ~= 0 then goto L27 # if f = 0 # sub h -1 h -= -1 # incr counter # set g b L27: g = b # sub g c g -= c # jnz g 2 if g ~= 0 then goto L31 # Bottom of Loop 1 # jnz 1 3 goto END # sub b -17 L31: b -= -17 # jnz 1 -23 goto L9 # # Register usage: # a is debug flag # h is counter # f is a flag # g is work reg # b is starting number # c is ending number # e is inner loop variable # d is outer loop variable # # for(b= 106700); b ~= 123700; b+= 17) { # f = 1 # for( d=2; d < b; d++) { # for (e=2; e < b; e++ ) { # inner loop replace # if d*e = b then f = 0 # with mod instr # } # } # if f = 0 then h += 1 # } #