bfs.c

人智算法基本程序

/****************************************************************/
/*    NAME: Smith Surasmith                                     */
/*    ACCT: sls                                                 */
/*   EMAIL: [e-mail]                                    */
/*    FILE: bfs.C                                               */
/*    ASGN: C++ code                                            */
/*    DATE: Wed Jun 22 13:41:49 1994                            */
/****************************************************************/

/*
 * Copyright 1994, Brown University, Providence, RI
 * See end of file for full copyright information
 */

#include <State.H>
#include <Searches.H>
#include <Queue.H>


/****************************************************************/
/*                                                              */
/* Function Name: bfs                                           */
/* Parameters:    (State) start state                           */
/*                (State) goal state                            */
/* Returns:       (if success) the pointer to goal state        */
/*                (if fail)    0                                */
/* Effects:       search state space from the start state       */
/*                until goal is found or state space exhausted  */
/*                this is a BREADTH FIRST SEARCH, and it        */
/*                is NOT recursive.                             */
/*                                                              */
/****************************************************************/

State*
bfs (State* current, State* goal)
{
   Queue<State,Comparator> search_list;
   State* transition;
   
   if ((current == 0) || (goal == 0))
      return 0;
   
   for(;
       ((current != 0)  && (current->compare(goal) != State::EQUAL));
       search_list.remove(current))
      {
         for(transition = current->makeTransition(); 
             transition != 0;
             transition = current->makeTransition())
            {
               if (transition)
                  transition->mark();
               search_list.insert(transition);
            }
      }
   return current;
}


/*
 * Copyright 1994, Brown University, Providence, RI
 *
 * Permission to use and modify this software and its documentation for
 * any purpose other than its incorporation into a commercial product is
 * hereby granted without fee.  Permission to copy and distribute this
 * software and its documentation only for non-commercial use is also
 * granted without fee, provided, however, that the above copyright notice
 * appear in all copies, that both that copyright notice and this permission
 * notice appear in supporting documentation, that the name of Brown
 * University not be used in advertising or publicity pertaining to
 * distribution of the software without specific, written prior permission,
 * and that the person doing the distribution notify Brown University of
 * such distributions outside of his or her organization. Brown University
 * makes no representations about the suitability of this software for
 * any purpose.  It is provided "as is" without express or implied warranty.
 * Brown University requests notification of any modifications to this
 * software or its documentation.
 *
 * Send the following redistribution information:
 *
 *	Name:
 *	Organization:
 *	Address (postal and/or electronic):
 *
 * To:
 *	Software Librarian
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 *	Providence, RI 02912
 *
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 *
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 */