// Store the simulation state in a map of age => count.
(function :Map<Int,Int64> ageMap [:String file]
    (let [:Array<Int> list (map (.split (first (Util.readLines file)) ",") Std.parseInt)
            :Map<Int,Int64> theMap (new Map)]
        // special key -1 corresponds to total count
        (dictSet theMap -1 (Int64Helper.fromFloat list.length))
        (doFor age (range 9)
            (dictSet theMap age (Int64Helper.fromFloat 0)))
        (doFor age list
            (let [count (dictGet theMap age)
                    one (Int64Helper.fromFloat 1)]
            (dictSet theMap age #{count + one;}#)))
        theMap))

(function :Map<Int,Int64> stepAgeMap [:Map<Int,Int64> theMap]
    // Lanternfish are guaranteed to be between 0-8 years old
    (let [:Map<Int,Int64> newMap (new Map)]
        (dictSet newMap -1 (dictGet theMap -1))
        (doFor age (range 9)
            (let [count (dictGet theMap age)]
                (case age
                    // Lanternfish giving birth:
                    (0
                        (dictInc newMap 8 count)
                        (dictInc newMap -1 count)
                        (dictInc newMap 6 count))
                    (otherwise
                        (dictInc newMap (- age 1) count)))))
        newMap))
                    
(function :String countAfter [file days]
    (let [&mut ageMap (ageMap file)]
        (doFor i (range days)
            (set ageMap (stepAgeMap ageMap)))
        (Int64.toStr (dictGet ageMap -1))))