/*******************************************************************************++  LEDA 3.5+++  list_pq.h+++  Copyright (c) 1995, 1996, 1997  by  LEDA Software GmbH+  Postfach 151101, 66041 Saarbruecken, Germany+  All rights reserved.+ *******************************************************************************/#include <LEDA/basic.h>class __exportC list_pq_elem{  friend class __exportC list_pq;  GenPtr key;  GenPtr inf;  list_pq_elem* succ;  list_pq_elem* pred;  list_pq_elem(GenPtr k, GenPtr i, list_pq_elem* p, list_pq_elem* s)   { key = k;     inf = i;     pred = p;    succ = s;   }  LEDA_MEMORY(list_pq_elem)};#define PRIO_IMPL      list_pq#define PRIO_IMPL_ITEM list_pq_itemtypedef list_pq_elem* list_pq_item;#define PRIO_IMPL_DATA list_pq_item head;\                       int          count;#include <LEDA/impl/prio_impl.h>inline list_pq::list_pq()    { head = nil; count = 0; }inline list_pq::list_pq(int) { error_handler(1,"no list_pq(int) constructor");}inline list_pq::list_pq(int,int) { error_handler(1,"no list_pq(int,int) constructor");}inline list_pq::~list_pq() { clear(); }inline list_pq_item list_pq::first_item()              const { return head;   }inline list_pq_item list_pq::next_item(list_pq_item x) const { return x ? x->succ : 0;}inline GenPtr list_pq::key(list_pq_item it) const { return it->key; }inline GenPtr list_pq::inf(list_pq_item it) const { return it->inf; }inline void list_pq::del_min()  { del_item(find_min());   }inline void list_pq::decrease_key(list_pq_item it, GenPtr x)  { copy_key(x);  clear_key(it->key);  it->key = x;  }inline void list_pq::change_inf(list_pq_item it, GenPtr y){ copy_inf(y);  clear_inf(it->inf);  it->inf = y;  }inline int  list_pq::size()  const  { return count; }