/in/foo.cc: In member function 'void Solution::solute()':
/in/foo.cc:57:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
           for(int k = r-1; k >= l; k--){
                            ~~^~~~
/in/foo.cc:66:5: error: expected ';' before '}' token
     }
     ^