/in/foo.cc: In function 'void dfs(int, int)':
/in/foo.cc:30:10: warning: unused variable 'j' [-Wunused-variable]
    int i,j;
          ^
/in/foo.cc:47:17: warning: array subscript has type 'char' [-Wchar-subscripts]
   t=cn[a[0][wei]]+cn[a[1][wei]]+jin[wei+1];
                 ^
/in/foo.cc:47:31: warning: array subscript has type 'char' [-Wchar-subscripts]
   t=cn[a[0][wei]]+cn[a[1][wei]]+jin[wei+1];
                               ^