// TWO POINTER APPROCH void reverseString(vector<char>& s) { int start=0,end=s.size()-1; while(start<end) swap(s[start++],s[end--]); }
// TWO POINTER APPROCH void reverseString(vector<char>& s) { int start=0,end=s.size()-1; while(start<end) swap(s[start++],s[end--]); }