day18

day18

1.编程求 s=1!+2!+3!+…..+n!

>>> n = 5

>>> s = 0

>>> t = 1

>>> for i in range(1,n+1):

... t *= i

... s ++ t

 

2.钞票换硬币 把一元钞票换成一分、二分、五分硬币（每种至少一枚），有多种换法，分 别有哪些？

>>> result = []

>>> count = 0

>>> for i in range(int(remain/1)):

... for j in range(int(remain/2)):

... for k in range(int(remain/5)):

... if(i + 2*j +k*5) == 92:

... count += 1

... result.append((i,j,k))

 

3.自己实现在一句话中查找某个单词的算法，存在返回索引号，否则返回 False

s = "you are a beautiful girl good"

def find_word(s, word):

word_len = len(word)

for i in range(len(s)):

if s[i:i+word_len] == word:

return i

return False

 

4.读入一个十进制整数，实现十进制转二进制算法将其转成二进制数 要求：不能使用现成进制转换函数，自己写代码实现

def dec_to_bin(num):

if isinstance(num, int):

result = []

while True:

temp = num % 2

num = num // 2

result.append(str(temp))

if num == 0:

break

return result[::-1]