/in/foo.cc: In function 'Sol solve(ll, ll)':
/in/foo.cc:12:29: error: could not convert '{1, (- q)}' from '<brace-enclosed initializer list>' to 'Sol'
     if (r==1) return {1,(-q)};
                             ^
/in/foo.cc:14:32: error: could not convert '{sol.Sol::y, (sol.Sol::x - (sol.Sol::y * q))}' from '<brace-enclosed initializer list>' to 'Sol'
     return {sol.y,sol.x-sol.y*q};
                                ^