\insert 'Visualizer.oz'
\insert 'List.oz'
\insert 'ApplyMoves.oz'
\insert 'Find.oz'

%FewerFind

declare

fun {FewerFind Ms Os Ts Ys}
   case Ys
   of nil then nil
   [] Y|Yr then
      if {Member Ms Y} then
     case {SplitTrain Ms Y}
     of Hs#Tr then
        local HsL TrL
        in
           HsL = {Length Hs}
           TrL = {Length Tr}

           trackA(TrL+1)|trackB(HsL)|trackA(~1)|{FewerFind nil Hs Tr Yr}
        end
     end
      elseif {Member Os Y} then
     case {SplitTrain Os Y}
     of Hs#Tr then
        local HsL TrL
        in
           HsL = {Length Hs}
           TrL = {Length Tr}

           trackB(~HsL)|trackA(HsL)|trackB(~1)|{FewerFind nil Tr {Append Hs Ts} Yr}
        end
     end
      elseif {Member Ts Y} then
     case {SplitTrain Ys Y}
     of Hs#Tr then
        local HsL TrL
        in
           HsL = {Length Hs}
           TrL = {Length Tr}

           trackA(~HsL)|trackB(HsL)|trackA(~1)|{FewerFind nil {Append Hs Os} Tr Yr}
        end
     end
      end
   end
end
{Browse {FewerFind [a b] nil nil [b a]}}