/in/foo.cc: In function 'int addnode(int, int)':
/in/foo.cc:63:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int pushup(int)':
/in/foo.cc:73:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int ref(int)':
/in/foo.cc:79:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int swap(int, int)':
/in/foo.cc:86:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int del()':
/in/foo.cc:94:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int pushdown(int)':
/in/foo.cc:101:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
  if (heap[x].v<heap[ls].v&&ls<=total)
     ^
/in/foo.cc:117:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^