class Solution:
def reverseString(self, s: List[str]) -> None:
# Time : o(n) | Space : o(1)
# return s.reverse()
# Time : o(n ^ 2) | Space : o(1)
# for i, e in enumerate(s):
# val = s.pop(i)
# s.insert(0, val)
# Time : o(n) | Space : = O(1)
left, right = 0, len(s) - 1
while left < right:
s[left], s[right] = s[right], s[left]
left += 1
right -= 1
return s