二分法從數組中查找指定元素

# -*- encoding: utf-8 -*-
# 二分法從數組中查找指定元素
def test(array,K):
	
	i = 0
	l = 0	# 數組最左邊記爲 0
	r = len(array)	# 數組最右邊

	while(1+l != r):
	
		i = (l+r)/2
		if (array[i] < K):
			l = i
		elif (array[i] > K):
			r = i
		elif (array[i] == K):
			return i
		
	return -1	# 否則返回 -1 


array = [1,3,5,7,9,11,13,15,17,19,21,23]
K=17	
a = test(array,K)
print a