题解 | #反转字符串#

#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 反转字符串
# @param str string字符串 
# @return string字符串
#
class Solution:
    def solve(self , str: str) -> str:
        # write code here
        if not str:
            return ""
        nums = list(str)
        i = 0
        j = len(nums)-1
        while i < j:
            nums[i], nums[j] = nums[j], nums[i]
            i += 1
            j -= 1
        return ''.join(nums)
#         return str[::-1]  # 一行解决字符串反转，没有额外空间