/in/foo.cc: In function 'void getsa()':
/in/foo.cc:21:28: warning: array subscript has type 'char' [-Wchar-subscripts]
  for(i=1;i<=N;i++) cnt[s[i]]=1;
                            ^
/in/foo.cc:23:32: warning: array subscript has type 'char' [-Wchar-subscripts]
  for(i=N;i;i--) rnk[i]=cnt[s[i]];
                                ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:56:11: warning: unused variable 'j' [-Wunused-variable]
     int i,j,k;
           ^
/in/foo.cc:56:13: warning: unused variable 'k' [-Wunused-variable]
     int i,j,k;
             ^