leetcode Reverse String

class Solution(object):
def reverseString(self, s):
"""
:type s: str
:rtype: str
"""
if s is None:
return None

if len(s) == 1:
return s

s = s[::-1]

return s

class Solution(object):
def reverseString(self, s):
"""
:type s: str
:rtype: str
"""
if s is None:
return None

if len(s) == 1:
return s

string_list = list(s)
string_list.reverse()

return ''.join(string_list)

class Solution {
public:
string reverseString(string s) {

int len = s.length();
for (int i = 0; i < len/2; i++) {
char c = s[i];
s[i] = s[len -1 - i];
s[len-1-i] = c;
}
return s;

}
};