1. 二分法查找

def binary_serch(list_,item):
    low=0
    high=len(list_)-1
    if list_[-1]==item:
            return high
    while low<high:
        num=low+int((high-low)/2)#向下取整
        
        guess=list_[num]
        if guess==item:
            return num 
        if guess>item:
            high=num  
        if guess<item:
            low=num  
        # item_=list
if __name__=='__main__':
    a=[1,4,6,8,10,11,23,100,230,1000]
    print(binary_serch(a,6))
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

2. 冒泡排序

def bubble_sort(list_):
    num=len(list_)
    for i in range(num):
        # print(i,num)
        for j in range(num-i-1):
            print(j)
            m=list_[j]
            n=list_[j+1]
            if m>n:
                list_[j+1]=m
                list_[j]=n
    return list_
if __name__=='__main__':
    a=[1,4,6,8,10,11,23,100,230,1000]
    print(bubble_sort(a))
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

3. 散列表，就是Python里的字典。
4. 递归练习：利用递归求出列表中所有值的和

def recursion_sum(list_):
    num=len(list_)
    if num>1:
        sum_=list_[0]+recursion_sum(list_[1:])
        return sum_
    if num==1:
        return list_[0]
def sum1(arr):
	if arr:
		return arr[0] + sum1(arr[1:])
	else:
		return 0

if __name__=='__main__':
    a=[1]
    # print(sum1(a))
    print(recursion_sum(a))
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

5. 快速排序：一种常用排序算法，比选择排序快的多。

6. python语法学习

• 三元运算符，在c/c++里使用

a=2
b=3
max=a>b?a:b
1
2
3

• 列表循环, 借助该语句可以形成一个新列表，适用python

array=[1,4,2]
pivot=1
new_array=[i for i in array[1:] if i < pivot]
1
2
3

• lambda表达式,，均适用

max=lambda x,y:x if x>y else y 
1

• 直接判断句，适用python

a=3
b=2
small=a if a<b else b
1
2
3

7. 广度优先搜索
   点击上述链接进行学习，自己写的代码如下

def person_is_mango_seller(person):
    if person=="thom":
        return True 
    else:
        return False  
if __name__=='__main__':
    graph={} # 字典
    graph["you"]=["alice","bob","claire"]
    graph["bob"]=["anuj","you","peggy"]
    graph["claire"]=["you","thom","jonny"]
    graph["anuj"]=["bob"]
    graph["peggy"]=["bob","alice"]
    graph["thom"]=["claire"]
    graph["jonny"]=["claire"]
    graph["alice"]=["you","peggy"]

    searched=[]
    search_quede=deque()
    search_quede+=graph["you"]
    searched.append("you")

    while search_quede:
        name=search_quede.popleft()
        if not name in searched:
            searched.append(name)
            if person_is_mango_seller(name):
                print(name,"is a mango seller!")
                break 
            else:
                search_quede+=graph[name] 
    print(searched)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31