programming-examples/python/Algorithms/Python program for binary search for an ordered list.py
2019-11-15 12:59:38 +01:00

34 lines
1015 B
Python

def Ordered_binary_Search(olist, item):
if len(olist) == 0:
return False
else:
midpoint = len(olist) // 2
if olist[midpoint] == item:
return True
else:
if item < olist[midpoint]:
return binarySearch(olist[:midpoint], item)
else:
return binarySearch(olist[midpoint+1:], item)
def binarySearch(alist, item):
first = 0
last = len(alist) - 1
found = False
while first <= last and not found:
midpoint = (first + last) // 2
if alist[midpoint] == item:
found = True
else:
if item < alist[midpoint]:
last = midpoint - 1
else:
first = midpoint + 1
return found
print(Ordered_binary_Search([0, 1, 3, 8, 14, 18, 19, 34, 52], 3))
print(Ordered_binary_Search([0, 1, 3, 8, 14, 18, 19, 34, 52], 17))