先 sort(s, s + 4);

if (s[0] == s[1] && s[1] == s[2] && s[2] == s[3]) {
            cout << "square" << endl;
        } else if (s[0] == s[1] && s[2] == s[3]) {
            cout << "rectangle" << endl;
        } else if (s[0] + s[1] + s[2] > s[3]) {
            cout << "quadrangle" << endl;
        } else {
            cout << "banana" << endl;
        }