Find first missing positive: Difference between revisions
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(→{{header|JavaScript}}: Switched from `Array.includes` to `Set.has`) |
(→{{header|Haskell}}: Added a variant in which the predicate is defined over a set, rather than a list.) |
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[7, 8, 9, 11, 12] |
[7, 8, 9, 11, 12] |
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]</lang> |
]</lang> |
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and if xs were large, it could be defined as a set: |
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<lang haskell>import Data.Set (fromList, notMember) |
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---------- FIRST MISSING POSITIVE NATURAL NUMBER --------- |
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firstGap :: [Int] -> Int |
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firstGap xs = head $ filter (`notMember` seen) [1 ..] |
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where |
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seen = fromList xs</lang> |
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{{Out}} |
{{Out}} |
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Same output for '''notElem''' and '''notMember''' versions above: |
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<pre>[1,2,0] -> 3 |
<pre>[1,2,0] -> 3 |
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[3,4,-1,1] -> 2 |
[3,4,-1,1] -> 2 |
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