/in/foo.cc: In function 'int main()':
/in/foo.cc:21:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if(mac.size()==n) {
       ~~~~~~~~~~^~~
/in/foo.cc:27:50: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   printf("For %d# problem we need%d\n",m-T+1,ans);
                                                  ^