比较熟悉了。
但要注意细节，
二分查找时，普通方法mid处理，递归时，mid处理。
# coding = utf-8
def sequential_search(a_list, item):
pos = 0
found = False
while pos < len(a_list) and not found:
if a_list[pos] == item:
found = True
pos += 1
return found
print('===========顺序查找==========')
test_list = [1, 2, 32, 8, 17, 10, 42, 13, 0]
print(sequential_search(test_list, 3))
print(sequential_search(test_list, 13))
def ordered_sequential_search(a_list, item):
pos = 0
stop = False
found = False
while pos < len(a_list) and not found and not stop:
if a_list[pos] == item:
found = True
if a_list[pos] > item:
stop = True
pos += 1
return found
print('===========已排序顺序查找==========')
test_list = [1, 2, 32, 33, 47, 53, 62, 73, 90]
print(ordered_sequential_search(test_list, 32))
print(ordered_sequential_search(test_list, 13))
'''
def binary_search(a_list, item):
begin = 0
end = len(a_list) - 1
found = False
while begin <= end and not found:
mid = (begin + end) // 2
if a_list[mid] > item:
end = mid - 1
elif a_list[mid] < item:
begin = mid + 1
else:
found = True
return found
'''
def binary_search(a_list, item):
if len(a_list) == 0:
return False
else:
mid = len(a_list) // 2
if a_list[mid] > item:
return binary_search(a_list[:mid], item)
elif a_list[mid] < item:
return binary_search(a_list[mid+1:], item)
else:
return True
print('===========二分查找==========')
test_list = [1, 2, 32, 33, 47, 53, 62, 73, 90]
print(binary_search(test_list, 32))
print(binary_search(test_list, 13))
C:\Users\Sahara\.virtualenvs\test\Scripts\python.exe C:/Users/Sahara/PycharmProjects/test/python_search.py ===========顺序查找========== False True ===========已排序顺序查找========== True False ===========二分查找========== True False Process finished with exit code 0