344.反转字符串
非常基本的题不做过多赘述。
class Solution:
def reverseString(self, s: List[str]) -> None:
"""
Do not return anything, modify s in-place instead.
"""
left, right = 0, len(s) - 1
while left < right:
s[left], s[right] = s[right], s[left]
left += 1
right -= 1
重点：理解p + k的范围
class Solution:
def reverseStr(self, s: str, k: int) -> str:
p = 0
while p < len(s):
p2 = p + k
s = s[:p] + s[p:p2][::-1] + s[p2:]
p += 2 * k
return s
class Solution:
def reverseWords(self, s: str) -> str:
words = s.split()
left, right = 0, len(words) - 1
while left < right:
words[left], words[right] = words[right], words[left]
left += 1
right -= 1
return ' '.join(words)
