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()))
青蛙跳台阶
一只青蛙一次可以跳上1级台阶,也可以跳上2级……它也可以跳上n级。求该青蛙跳上一个n级的台阶总共有多少种跳法。
fib = lambda n: n if n < 2 else 2 * fib(n - 1)
快排
#! /usr/bin/env python
# -*- coding: utf-8 -*-
def quick(list):
if len(list) < 2:
return list
tmp = list[0] # 临时变量 可以取随机值
left = [x for x in list[1:] if x <= tmp] # 左列表
right = [x for x in list[1:] if x > tmp] # 右列表
return quick(left) + [tmp] + quick(right)
li = [4,3,7,5,8,2]
print quick(li) # [2, 3, 4, 5, 7, 8]
#### 对[4,3,7,5,8,2]排序
'''
[3, 2] + [4] + [7, 5, 8] # tmp = [4]
[2] + [3] + [4] + [7, 5, 8] # tmp = [3] 此时对[3, 2]这个列表进行排序
[2] + [3] + [4] + [5] + [7] + [8] # tmp = [7] 此时对[7, 5, 8]这个列表进行排序
'''