题目
Write a function that reverses a string. The input string is given as an array of characters char[].
Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
You may assume all the characters consist of printable ascii characters.
解题思路
- 使用两个指针，指向头尾字符，进行交换，头指针+1，尾指针-1
- 使用一个指针，第
i个字符要和第-i-1个字符交换
代码
# two pointers
class Solution:
def reverseString(self, s: List[str]) -> None:
"""
Do not return anything, modify s in-place instead.
"""
l, r = 0, len(s) - 1
while l < r:
s[l], s[r] = s[r], s[l]
l += 1
r -= 1
# one pointer
class Solution:
def reverseString(self, s: List[str]) -> None:
"""
Do not return anything, modify s in-place instead.
"""
for i in range(len(s) // 2):
s[i], s[-i - 1] = s[-i - 1], s[i]
