344. Reverse String

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.

class Solution {
public:
    void reverseString(vector<char>& s) {
        for(int i = 0; i < s.size() / 2; i++) {
            swap(s[i],s[s.size()-1-i]);
        }
    }
};