Alpine wasn't that fast...

time(1) just shows fewer decimal places than bash's time, and
I didn't notice!

day08.nim

         child_values.add(res.value)
         metasum += res.metasum
 
-    for m in 0..meta_count-1:
+    for m in 0 .. meta_count - 1:
         var v = input.pop.parseInt
         if v > 0 and v <= child_count:
             value += child_values[v - 1]

docker/Dockerfile

-FROM nimlang/nim:alpine
-
-RUN apk update && apk add bash
+FROM nimlang/nim:slim
 
 ADD entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh

run.sh

 #!/bin/bash
 
-IMAGE=csmith/aoc-2018-05
+IMAGE=csmith/aoc-2018-06
 
 docker image inspect $IMAGE >/dev/null 2>&1
 if [ $? -ne 0 ]