/in/foo.cc: In function 'int main()':
/in/foo.cc:41:38: warning: 'righ' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (p) ans=max(ans,(down-x+1)*(righ-y+1)); 
                                  ~~~~^~
/in/foo.cc:43:14: warning: 'lef' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (down!=x&&lef!=y)
       ~~~~~~~^~~~~~~~
/in/foo.cc:43:3: warning: 'down' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (down!=x&&lef!=y)
   ^~
/in/foo.cc:31:3: warning: 'up' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (up!=x&&righ!=y)
   ^~