binary search

binary_search.rb

#binary search

def binary_search(item,array,min = 0,max = array.length, half = (min + max) / 2)
	return min if item == array[min]
	return -1 if (item < array[0] || item > array[array.length-1]) || (min == max - 1)
	item < array[half] ? binary_search(item,array,min,half) : binary_search(item,array,half,array.length)
end

test_array = (1..15).to_a
puts binary_search(13,test_array) == 12

test_array = (100..200).to_a
puts binary_search(135, test_array) == 35

test_array = [13, 19,  24,  29,  32,  37,  43]
puts binary_search(35, test_array) == -1

test_array = [-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7]
puts binary_search(-3, test_array) == 2
puts binary_search(3, test_array) == 8