3-white-and-3-black-tiles-problem.algorithm

Selector:= white    
Foreach black tile b
     do h(b):= tile-distance to the first white tile to its right
Foreach white tile w
     do h(w):= tile-distance to the first black tile to its left * -1
 
While any tile has a non-zero h value
   Do
        If selector:= white then,
            Select the while-tile with the highest h value, say X
            If the h(X):= 0 and it does not have the blank space to its left then,
                Select another while-tile with the next-highest h value, say X
            Selector := black
        Else
            Select the black-tile with the highest h value, say X
            If the h(X):= 0 and it does not have the blank space to its left then,
                Select another black-tile with the next-highest h value, say X
            Selector:= white
 
       If X and the blank space is in 2-tiles distance then,
           Move X to the blank space and record the cost
 
       Foreach black tile b
           do h(b):= tile-distance to the first white tile to its right
       Foreach white tile w
           do h(w):= tile-distance to the first black tile to its left * -1
End while

can you share java or python implementation on this that help me a lots? plz