/in/foo.cc: In function 'int solve(int, int, int)':
/in/foo.cc:67:8: warning: operation on 'temp' may be undefined [-Wsequence-point]
   temp = temp ? temp-- : (m-1);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:49:6: warning: unused variable 'sum' [-Wunused-variable]
  int sum;   //房间总和 
      ^~~