def answer(list, key):
if len(list) <= 0:
return -1
if len(list) == 1:
return 0
if key == list[0]:
return 0
length = len(list)
if key == list[length -1]:
return length-1
length = len(list)
low = 0
high = length-1
mid = int(length/2)
if key < list[mid]:
return(BinarSearch(list, low, mid, key))
elif key > list[mid]:
return(BinarSearch(list, mid, high, key))
elif key == list[mid]:
return mid
def BinarSearch(list, low, high, key):
for low in range(high):
if list[low] == key:
return low
return -1
