Remove unused statement

strategy.py

@@ -206,13 +206,11 @@ class State:
 
         colors = {}
         groups = {}
-        groupsizes = {}
 
         for groupid, (block, group) in enumerate(self.find_groups(depth, 1)):
             colors.setdefault(block, []).extend(group)
             for i in group:
                 groups[i] = groupid
-                groupsizes[i] = len(group)
 
         return sum(dist(i, j)
                    for block, color in colors.items()