queen.cpp

解决有名的皇后问题

#include <math.h>
#include <stdio.h>
int record[8];
int n=8,top=0,count=0;

void push(int column)
{
	record[top]=column;
	top++;
}

void pop()
{
	top--;
	record[top]=0;
}

int fixed(int line,int column)
{
	int buf_line;
	for(buf_line=0;buf_line<top;buf_line++)
	{
		if(abs(record[buf_line]-column)==abs(buf_line-line))
			break;
	}
	if(buf_line==top)
	{	
		for(buf_line=0;buf_line<top;buf_line++)
		{
			if(record[buf_line]==column)
			break;
		}
		if(buf_line==top)
			return 1;
		else 
			return 0;
	}
	else 
		return 0;
}

void pbuffer()
{
	int buf_line;
	for(buf_line=0;buf_line<n;buf_line++)
		printf("%d  ",record[buf_line]);
	printf("\n");
	pop();
	count++;
}

void go(int line)
{
	int column;
	if(line<n-1)
	{
		for(column=0;column<n;column++)
		{
			if(fixed(line,column))
			{
				push(column);
				go(line+1);
				pop();
			}
		}
	}
	else
	{
		for(column=0;column<n;column++)
		{
			if(fixed(line,column))
			{
				push(column);
				pbuffer();
				break;
			}
		}
	}
}

int main()
{
	go(0);
	if(count==0)
		printf("Not found!!\n");
	else
		printf("%d  cases found.\n",count);
	return(0);
}