Difference between revisions of "Solution2.html"
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(Explained an incorrect solution,) |
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</haskell> |
</haskell> |
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| − | This solution will not work. If the sheep has a father and only a maternal grandparent, this function will return Nothing: |
+ | This next solution will not work. If the sheep has a father and only a maternal grandparent, this function will return Nothing: |
<haskell> |
<haskell> |
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grandparent :: Sheep -> Maybe Sheep |
grandparent :: Sheep -> Maybe Sheep |
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Revision as of 17:49, 10 June 2013
parent :: Sheep -> Maybe Sheep
parent s = father s `mplus` mother s
grandparent :: Sheep -> Maybe Sheep
grandparent s = paternalGrandfather s `mplus`
paternalGrandmother s `mplus`
maternalGrandfather s `mplus`
maternalGrandmother s
This next solution will not work. If the sheep has a father and only a maternal grandparent, this function will return Nothing:
grandparent :: Sheep -> Maybe Sheep
grandparent s = parent s >>= parent