main.cpp.bak

数据结构 八皇后问题解决方案一 很好的代码

#include<iostream.h>
#include"EightQueens.h"
#include"time.h"
void main()
/*
Pre:  The user enters a valid board size.
Post: All solutions to the n-queens puzzle for the selected
      board size are printed.
Uses: The class Queens and the recursive function solve_from.
*/
{
   int board_size;
   void solve_from(Queens &configuration);
   void print_information();
   print_information();
   cout << "What is the size of the board? " << flush;
   cin  >> board_size;
   double start=time(NULL);
   if (board_size < 0 || board_size > max_board)
      cout << "The number must be between 0 and " << max_board << endl;
   else {
      Queens configuration(board_size); //   Initialize empty configuration.
      solve_from(configuration);  //  Find all solutions extending configuration.
   }
   double end=time(NULL);
   cout<<"It takes time: "<<(end-start)<<"(s)"<<endl;
}

void print_information()
{
	cout<<"This is the Queens game."<<endl;
}

void solve_from(Queens &configuration)
/*
Pre:  The Queens configuration represents a partially completed
      arrangement of nonattacking queens on a chessboard.
Post: All n-queens solutions that extend the given configuration are printed.
      The configuration is restored to its initial state.
Uses: The class Queens and the function solve_from, recursively.
*/
{
   if (configuration.is_solved()) configuration.print();
   else
      for (int col = 0; col < configuration.board_size; col++)
         if (configuration.unguarded(col)) {
            configuration.insert(col);
            solve_from(configuration);   //   Recursively continue to add queens.
            configuration.remove(col);
         }
}