#include <stdlib.h>        #include "fatal.h"        typedef int ElementType;        #define Infinity 32767        #ifndef _Treap_H        #define _Treap_H        struct TreapNode;        typedef struct TreapNode *Position;        typedef struct TreapNode *Treap;        Treap MakeEmpty( Treap T );        Position Find( ElementType X, Treap T );        Position FindMin( Treap T );        Position FindMax( Treap T );        Treap Initialize( void );        Treap Insert( ElementType X, Treap T );        Treap Remove( ElementType X, Treap T );        ElementType Retrieve( Position P );        extern Position NullNode;        #endif  /* _Treap_H *//* END */