ms100-not-sure-which-one

gistfile1.txt

''' 给定一个字符串，

要求把字符串前面的若干个字符移动到字符串的尾部，如把字符串“abcdef”前面的2个字符'a'和'b'移动到字符串的尾部，
使得原字符串变成字符串“cdefab”。

请写一个函数完成此功能，

要求对长度为n的字符串操作的时间复杂度为 O(n)，空间复杂度为 O(1)。 '''


input = 'abcdef'

r = input[2:] + input[0] + input[1]
print(r)

gistfile2.txt

''' 有个长度为2n的数组{a1,a2,a3,...,an,b1,b2,b3,...,bn}，希望排序后{a1,b1,a2,b2,....,an,bn}，请考虑有无时间复杂度o(n)，空间复杂度0(1)的解法。 '''


a1 = ['a1', 'a2', 'a3', 'a4', 'b1', 'b2', 'b3', 'b4']

# seperate 2 list via prefix
list1 = [ele for ele in a1 if ele.startswith('a')]
print(list1)
list2 = [ele for ele in a1 if ele.startswith('b')]
print(list2)

# loop them one by one to add to third list
x = [*sum(zip(list1, list2), ())]
print(x)

string1.py

''' 单词翻转题：输入“I am a student.”，则输出“student. a am I”。 '''


input = 'I am a student'


# seperate sentence into each word

list_ = input.split(" ")
list_.reverse()
print(list_)
result = ' '.join(list_)
print(result)

# put them into a list
# read that list in reverse oder and concate them up