测试第二个月:python算法归类
1.斐波那契数列
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
2.二分法
def func(alist, item):
low = 0
high = len(alist)-1
print(type(low))
n = 0 # 记录查询几次查到
while low <= high: # 循环的次数小于或者等于high的时候停止循环
mid = int((low + high)/2)
n += 1 # 没查询一次 查询次数+1
if alist[mid]==item: # 比对中间值是否等于要查询的参数
return mid # 如果是 直接返回值
if alist[mid]<item: # 判断如果中间值小于要查询得数
low = mid + 1 #那么循环开始的数low 就等于 中间值+1
else:
high = (mid-1) # 如果大于 就把中间值数的下标-1 缩小查询范围
return None #如果什么都没有查到 返回None
print(func([1,2,33,4,58,9,11,12,19,18,89,20,28],28)) # 输出查询到的值
二分法 迭代查询
def fun(alist,item):
if len(alist) == 0:
return False
else:
mid = len(alist) // 2 #获取中间值的下标
if item == alist[mid]:
return True,item
elif item < alist[mid]: # 如果查找的数小于中间值
return fun(alist[:mid],item) #从开头到中间值查询 [:mid]是中间值66往前得数
else:
return fun(alist[mid+1:],item) # 否则从中间值下一个数到结尾
# 输出返回的值
print(fun([1, 22,33,44,55,66,77,88,99],66))
3.等边三角形
for i in range(1,6):
for j in range(1,6-i):
print(" ",end="")
for k in range(1,i+1):
print("* ",end="")
print("")
等边三角形二
for i in range(1,6):
for j in range(1,6-i):
print(" ",end="")
print("* "*i)
4.直角三角形
for i in range(6):
i += 1
for j in range(i):
print('*', end='')#end=‘'输出空格
print()
5.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]))
6.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]))
7.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()))
8.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。
#! /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
'''

浙公网安备 33010602011771号