--- /dev/null
+module one
+
+import StdEnv
+
+read :: *File -> [Instr]
+read f
+ # (l, f) = freadline f
+ | l.[size l - 1] <> '\n' = []
+ = [toInstr [c\\c<-:l | c <> '\n']:read f]
+where
+ toInstr ['nop ':rs] = Nop (toInt (toString rs))
+ toInstr ['acc ':rs] = Acc (toInt (toString rs))
+ toInstr ['jmp ':rs] = Jmp (toInt (toString rs))
+
+:: Instr = Nop Int | Acc Int | Jmp Int
+
+Start w
+ # (io, w) = stdio w
+ # instr = read io
+ # instr = {c\\c<-instr}
+ = (one instr, two instr)
+
+one = fst o interpret
+two = hd o filter snd o map interpret o nopjump 0
+
+nopjump :: Int {Instr} -> [{Instr}]
+nopjump pc is
+ | pc == size is = []
+ = case is.[pc] of
+ Nop i = [update {i\\i<-:is} pc (Jmp i):nopjump (pc+1) is]
+ Jmp i = [update {i\\i<-:is} pc (Nop i):nopjump (pc+1) is]
+ _ = nopjump (pc+1) is
+
+interpret :: {Instr} -> (Int, Bool)
+interpret instr = int [] 0 0
+where
+ int vis pc acc
+ | pc >= size instr = (acc, True)
+ | isMember pc vis = (acc, False)
+ = case instr.[pc] of
+ Nop _ = int [pc:vis] (1 + pc) acc
+ Acc i = int [pc:vis] (1 + pc) (i + acc)
+ Jmp i = int [pc:vis] (i + pc) acc