Find index of number (two different methods)

find_index.rb

# N is number of elements
# N

# O(N)

def find_index(number, numbers)
  numbers.each_with_index do |n, i|
    if n == number
        return i
    end
    return nil
  end
end



# assume that numbers are sorted
# O(log N)

def find_index(number, numbers)

    first = 0
    last = numbers.length-1
    middle = last / 2

    loop do
        puts "#{first}, #{middle}, #{last}"
        if numbers[middle] < number
            first = middle
            middle = first +  ( (last - middle) / 2 )
        elsif numbers[middle] > number
            last = middle
            middle = (middle - first) / 2
        else
            return numbers[middle]
        end
        break if numbers[middle] == number
    end

    if number == numbers[middle]
        return numbers[middle]
    else
        return nil
    end

end

puts find_index(15, [1, 4, 7, 9, 12, 15, 22, 55, 453, 1000])