# -*- coding: utf-8 -*-
number_list = [0, 1, 2, 3, 4, 5, 6, 7]
def linear_search(value, iterable):
for index, val in enumerate(iterable):
if val == value:
return index
return -1
assert linear_search(5, number_list) == 5
def linear_search_v2(predicate, iterable):
for index, val in enumerate(iterable):
if predicate(val):
return index
return -1
assert linear_search_v2(lambda x: x == 5, number_list) == 5
def linear_search_recusive(array, value):
if len(array) == 0:
return -1
index = len(array)-1
if array[index] == value:
return index
return linear_search_recusive(array[0:index], value)
assert linear_search_recusive(number_list, 5) == 5
assert linear_search_recusive(number_list, 8) == -1
assert linear_search_recusive(number_list, 7) == 7
assert linear_search_recusive(number_list, 0) == 0
def binary_search_recursive(sorted_array, beg, end, val):
if beg >= end:
return -1
mid = int((beg + end) / 2) # beg + (end-beg)/2
if sorted_array[mid] == val:
return mid
elif sorted_array[mid] > val:
return binary_search_recursive(sorted_array, beg, mid, val)
else:
return binary_search_recursive(sorted_array, mid+1, end, val)
def test_binary_search_recursive():
a = list(range(10))
for i in a:
assert binary_search_recursive(a, 0, len(a), i) == i
assert binary_search_recursive(a, 0, len(a), -1) == -1
assert binary_search_recursive(a, 0, len(a), 10) == -1
