52 lines
1.4 KiB
Text
52 lines
1.4 KiB
Text
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!mod Leetcode
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@doc
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LeetCode #1: two_sum
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TODO: store a map of complements (differences) as iterating for O(n)
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fn two_sum _:list _:int i=0 ::
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[] _ _ -> nil
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[cur | rest] target current_index
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Enum.find_index rest, fn x -> cur + x == target ::
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nil -> two_sum rest target current_index
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i -> [current_index, 1 + current_index + i]
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@doc LeetCode #2: add_two_numbers
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fn add_two_numbers _:list _:list _=[] i=0 ::
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[] _ l m, _ [] l m -> finish_add_two_numbers l m
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[n1 | r1] [n2 | r2] l carry
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add_two_numbers r1 r2 [rem (carry + n1 + n2) 10) | l] (div n1 + n2 10)
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fn finish_add_two_numbers l:list m:int -> m == 0 ? l : [m | l]
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@doc
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LeetCode #3: longest non-repeating susbtring
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TODO: better utility function names?
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fn longest_non_repeating_substring s
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s |> String.codepoints |> Enum.reduce {0 0 0 %{}} &ln3_reducer/2 |> elem 0
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fn ln3_new_least least map char
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Map.has_key? map char ? max least ((Map.get map char) + 1) : least
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fn ln3_reducer char {mx i least map}
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least = ln3_new_least least map char
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{(max mx (i - least + 1) (i + 1) least (Map.put map char i)}
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@doc
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LeetCode #4: median of sorted arrays
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TODO: solution should me O(log(m+n))
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TODO: finish an actual solution?
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fn median_of_sorted_arrays _ _ -> 3
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@doc LeetCode #65: Valid Number
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@valid_decimal_number_regex ~r/^\s*(?:\+|-)?\d+(?:\.(?=\d))?\d*(?:e(?=[\d\+-]))?(?:\+|-)?\d*(?:\.(?=\d))?\s*$/
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fn valid_decimal_number s -> Regex.match? @valid_decimal_number_regex s
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