%%% EX 6
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this is DFS search in the space of actions, not ion a pre-build graph!
also several errors
-explored data structure not initialized
-missing initial goal test
-it is node to me marked as explored, not its children

%%% EX 7
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unsolved

%%% EX 8
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ok

%%% EX 9
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a)unsolved
b)unsolved
c)unsolved
d)unsolved

%%% EX 10
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nonsense