class Solution {
public:
    bool is_palindrome(vector < char >& s){
    int l = 0, r = s.size() - 1;
    while(l < r)
        if(s[l++] != s[r--]) return false;
    return true;
}
    void print(){
        cout << (is_palindrome(s) ? "true" : "false");
    }
};