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47 lines
No EOL
1.6 KiB
Elixir
47 lines
No EOL
1.6 KiB
Elixir
# I’m thinking of a number between 1 and 1000.…
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# The most efficient way to find the number is to guess halfway between the low and high numbers of the range.
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# If our guess is too big, then the answer lies between the bottom of the range and one less than our guess.
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# If our guess is too small, then the answer lies between one more than our guess and the end of the range.
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# Your API will be guess(actual, range), where range is an Elixir range. Your output should look similar to this:
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#
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# iex> Chop.guess(273, 1..1000)
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# Is it 500
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# Is it 250
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# Is it 375
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# Is it 312
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# Is it 281
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# Is it 265
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# Is it 273
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# 273
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# Hints:
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# - You may need to implement helper functions with an additional parameter (the currently guessed number).
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# - The div(a,b) function performs integer division.
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# - Guard clauses are your friends.
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# - Patterns can match the low and high parts of a range (a..b=4..8).
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defmodule Chop do
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def guess(actual, range) do
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first..last = range
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guess = div(last + first, 2)
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guess(actual, first, last)
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end
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defp guess(actual, first, last) when actual < div(last + first, 2) do
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IO.puts "Is it #{div(last + first, 2)}"
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guess(actual, first, div(last + first, 2))
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end
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defp guess(actual, first, last) when actual > div(last + first, 2) do
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IO.puts "Is it #{div(last + first, 2)}"
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guess(actual, div(last + first, 2), last)
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end
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defp guess(actual, first, last) do
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IO.puts actual
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end
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end
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Chop.guess(273, 1..1000) |