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

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

class Solution {
public:
    void reverseString(vector<char>& s) {
       reverse(s.begin(),s.end());
    }
};

class Solution {
public:
    void reverseString(vector<char>& s) {
        char tmp;
        int left=0 ,right=s.size()-1;
        while(left<right)
        {
            tmp = s[right];
            s[right] = s[left];
            s[left] = tmp;
            left++;
            right--;
        }
        return ;
    }
};