/in/foo.cc: In function 'void Check()':
/in/foo.cc:24:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for (int i=1; i<=9; ++i) printf("%d ",a[i]);cout<<endl;
  ^~~
/in/foo.cc:24:46: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
  for (int i=1; i<=9; ++i) printf("%d ",a[i]);cout<<endl;
                                              ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:49:19: warning: unused variable 'U' [-Wunused-variable]
   int u=Q.front(),U=u,Step=find_hash(u);Q.pop();
                   ^