Python 算法

冒泡排序

def func(alist):
for x in range(1,len(alist)):
for i in range(0,len(alist)-x):
if alist[i] > alist[i+1]:
alist[i], alist[i+1] = alist[i+1], alist[i]
return alist
print(func([1,4,2,3,6,7,8,9,0,5]))

选择排序

def func(alist):
for x in range(0,len(alist)):
min_num = alist[x]
for i in range(x+1,len(alist)):
if alist[i] < min_num:
alist[i], min_num = min_num, alist[i]
alist[x] = min_num
return alist
print(func([1,4,2,3,6,7,8,9,0,5]))

斐波那契

def func(n):
a = 0
b = 1
alist = []
if n <= 2:
alist.append(a)
alist.append(b)
return alist
else:
for i in range(n):
alist.append(a)
a, b = b, a + b
return alist

print(func(9))

二分法
def func(alist, item):
low = 0
high = len(alist)-1
n = 0
while low <= high:
mid = int((low + high)/2)
n += 1
if alist[mid]==item:
return mid
if alist[mid]<item:
low = mid + 1
else:
high = (mid-1)
return None

m=[1,2,3,4,8,9,11,12,14,18,19,20,28]
print(func(m,14))

链表
class Node:
def init(self, initdata):
self.__data = initdata
self.__next = None

def getData(self):
    return self.__data

def getNext(self):
    return self.__next

def setData(self, newdata):
    self.__data = newdata

def setNext(self, newnext):
    self.__next = newnext

class SinCycLinkedlist:
def init(self):
self.head = Node(None)
self.head.setNext(self.head)

def add(self, item):
    temp = Node(item)
    temp.setNext(self.head.getNext())
    self.head.setNext(temp)

def remove(self, item):
    prev = self.head
    while prev.getNext() != self.head:
        cur = prev.getNext()
        if cur.getData() == item:
            prev.setNext(cur.getNext())
        prev = prev.getNext()

def search(self, item):
    cur = self.head.getNext()
    while cur != self.head:
        if cur.getData() == item:
            return True
        cur = cur.getNext()

    return False

def empty(self):
    return self.head.getNext() == self.head

def size(self):
    count = 0
    cur = self.head.getNext()
    while cur != self.head:
        count += 1
        cur = cur.getNext()

    return count

if name == 'main':
s = SinCycLinkedlist()
print('s.empty() == %s, s.size() == %s' % (s.empty(), s.size()))

s.add(19)
s.add(86)
print('s.empty() == %s, s.size() == %s' % (s.empty(), s.size()))

print('86 is%s in s' % ('' if s.search(86) else ' not',))
print('4 is%s in s' % ('' if s.search(4) else ' not',))
print('s.empty() == %s, s.size() == %s' % (s.empty(), s.size()))

s.remove(19)
print('s.empty() == %s, s.size() == %s' % (s.empty(), s.size()))