/in/foo.cc: In function 'bool hashs(unsigned int)':
/in/foo.cc:16:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(p==x%mod) return false; return true;
  ^~
/in/foo.cc:16:29: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
  if(p==x%mod) return false; return true;
                             ^~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:21:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<=n;i++) cin>>a[i];
              ~^~~
/in/foo.cc:22:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<=n;i++){
              ~^~~