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# IntegerGuesser.guess(number, range) | |
# Conducts a binary serach within the range for the integer and | |
# reports its path along the way. | |
# | |
# EX: | |
# iex(1)> IntegerGuesser.guess(273, 1..1000) | |
# Is it 500?... Nope | |
# Is it 249?... Nope | |
# Is it 375?... Nope | |
# Is it 311?... Nope | |
# Is it 279?... Nope | |
# Is it 263?... Nope | |
# Is it 271?... Nope | |
# Is it 275?... Nope | |
# Is it 272?... Nope | |
# Is it 274?... Nope | |
# Is it 272?... Nope | |
# "It's 273!" | |
defmodule IntegerGuesser do | |
def guess(actual, first..last) | |
when actual in first..last do | |
next_guess(actual, div(last, 2), first..last) | |
end | |
defp next_guess(actual, guess, _) | |
when guess == actual do | |
"It's #{guess}!" | |
end | |
defp next_guess(actual, guess, first..last) | |
when guess < actual do | |
report_guess(guess) | |
next_guess(actual, div(last+guess, 2)+1, guess+1..last) | |
end | |
defp next_guess(actual, guess, first..last) | |
when guess > actual do | |
report_guess(guess) | |
next_guess(actual, div(guess+first, 2)-1, first..guess-1) | |
end | |
defp report_guess(guess) do | |
IO.puts("Is it #{guess}?... Nope") | |
end | |
end |
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