记录一次耗时比较久的2种方法

Posted 2021-03-12 wenwen9090

待分析：内存与复杂度
问题：

有n个人围成一圈，顺序排号。从第一个人开始报数（从1到3报数），凡报到3的人退出圈子，问最后留下的是原来第几号的那位。

第一种解法：
#在成为领导者之前，成功的全部就是自我成长
#有n个人围成一圈，顺序排号。从第一个人开始报数（从1到3报数），凡报到3的人退出圈子，问最后留下的是原来第几号的那位。
#1.2.3.4.5,6 |1,2,4,5|1,2,5|1,5
#1,2,3,4,5
#1,2,3,4
#解决思路提供了三种情况的遍历，采用了递归的方式，但不得不说增加了很多额外变量的开销
def one_px(lst):
    length=len(lst)
    if(length%3==0):
        newlst = queue_n(lst)
    elif (length%3==1):
        newlst = queue_n1(lst)
    else:
        newlst = queue_n2(lst)
    if len(newlst)>=3:
        one_px(newlst) #递归
    else:
        print(newlst)
    return newlst


def queue_n(lst):
    l=len(lst)
    for i in range(l,-1,-1):
        if (i+1)%3==0:
            lst.remove(lst[i])
    print(‘n‘)
    print(lst)
    return lst

def queue_n2(lst):
    l=len(lst)
    for i in range(l-2,-1,-1):
        if (i + 1) % 3 == 0:
            lst.remove(lst[i])
    l = len(lst)
    temp1 = lst[l - 2]
    temp2 = lst[l-1]
    print(lst)
    for i in range(l-3,-1,-1):
        lst[i+2]=lst[i]
    lst[0]=temp1
    lst[1]=temp2
    print(‘n2‘)
    print(lst)
    return lst

def queue_n1(lst):
    l=len(lst)
    for i in range(l,-1,-1):
        if (i + 1) % 3 == 0:
            lst.remove(lst[i])
    print(lst)
    l=len(lst)
    temp=lst[l-1]
    for i in range(l-2,-1,-1):
        lst[i+1]=lst[i]
    lst[0]=temp
    print(‘n1‘)
    print(lst)
    return lst

if __name__==‘__main__‘:

　　lst=[]
　　#lst=[1,2,3,4,5,6,7,8,9,10]
　　for i in range(1,35):
    　　lst.append(i)
　　print(lst)
　　#while len(lst)>2:
　　print(one_px(lst)[1])

运行结果：

[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, 32, 33, 34]
[1, 2, 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32, 34]
n1
[34, 1, 2, 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32]
[34, 1, 4, 5, 8, 10, 13, 14, 17, 19, 22, 23, 26, 28, 31, 32]
n2
[31, 32, 34, 1, 4, 5, 8, 10, 13, 14, 17, 19, 22, 23, 26, 28]
[31, 32, 1, 4, 8, 10, 14, 17, 22, 23, 28]
n1
[28, 31, 32, 1, 4, 8, 10, 14, 17, 22, 23]
[28, 31, 1, 4, 10, 14, 22, 23]
n2
[22, 23, 28, 31, 1, 4, 10, 14]
[22, 23, 31, 1, 10, 14]
n2
[10, 14, 22, 23, 31, 1]
n
[10, 14, 23, 31]
[10, 14, 31]
n1
[31, 10, 14]
n
[31, 10]
[31, 10]
10

第二种解法：

#在成为领导者之前，成功的全部就是自我成长
#有n个人围成一圈，顺序排号。从第一个人开始报数（从1到3报数），凡报到3的人退出圈子，问最后留下的是原来第几号的那位。

if __name__==‘__main__‘:

    n=10
    lst=[]
    for i in range(n):
        lst.append(i+1)
    print(lst)
    i=0
    k=0
    m=0
while(m<n-1):
    if(lst[i]!=0):k+=1
    if(k==3):
        lst[i]=0
        k=0
        m+=1
    i+=1
    #print(i)
    if(i==n):i=0
    print(lst)
运行结果：

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
[1, 2, 0, 4, 5, 6, 7, 8, 9, 10]
[1, 2, 0, 4, 5, 6, 7, 8, 9, 10]
[1, 2, 0, 4, 5, 6, 7, 8, 9, 10]
[1, 2, 0, 4, 5, 0, 7, 8, 9, 10]
[1, 2, 0, 4, 5, 0, 7, 8, 9, 10]
[1, 2, 0, 4, 5, 0, 7, 8, 9, 10]
[1, 2, 0, 4, 5, 0, 7, 8, 0, 10]
[1, 2, 0, 4, 5, 0, 7, 8, 0, 10]
[1, 2, 0, 4, 5, 0, 7, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 7, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 7, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 7, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 7, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 7, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[1, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 8, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 5, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 10]
[0, 0, 0, 4, 0, 0, 0, 0, 0, 0]