题目
Write a function that reverses a string. The input string is given as an array of characters s
.
You must do this by modifying the input array in-place with O(1)
extra memory.
Example 1:
Input: s = ["h","e","l","l","o"]
Output: ["o","l","l","e","h"]
Example 2:
Input: s = ["H","a","n","n","a","h"]
Output: ["h","a","n","n","a","H"]
Constraints:
1 <= s.length <= 105
s[i]
is a printable ascii character.
思路
简单的前后字符替换。
代码
python版本:
class Solution:
def reverseString(self, s: List[str]) -> None:
"""
Do not return anything, modify s in-place instead.
"""
l=len(s)
for i in range(l//2):
s[i],s[l-i-1]=s[l-i-1],s[i]