private static void _add(Dictionary <int, List <Actions.ActionChain> > dest, Actions.ActionChain src)
{
int cost = src.CumulativeMoveCost();
if (dest.TryGetValue(cost, out var cache))
{
cache.Add(src);
}
else
{
dest.Add(cost, new List <Actions.ActionChain> {
src
});
}
}
