/in/foo.cc: In function 'int main()':
/in/foo.cc:17:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define rep(i,a,b) for(int i = (a);i < (b);i++)
                                      ^
/in/foo.cc:55:3: note: in expansion of macro 'rep'
   rep(i, 0, buf.size()){
   ^~~
/in/foo.cc:52:6: warning: unused variable 'N' [-Wunused-variable]
  int N, M, T, i, j, d;
      ^
/in/foo.cc:52:9: warning: unused variable 'M' [-Wunused-variable]
  int N, M, T, i, j, d;
         ^
/in/foo.cc:52:12: warning: unused variable 'T' [-Wunused-variable]
  int N, M, T, i, j, d;
            ^
/in/foo.cc:52:21: warning: unused variable 'd' [-Wunused-variable]
  int N, M, T, i, j, d;
                     ^