queen.java

八皇后的scheme

public class Queen
{
	public static void f(int [][]a,int start_line,int []counter)
		{

			if(start_line==8)
			{
				counter[0]++;
				System.out.println("Solution No."+counter[0]+":");
				for(int i=0;i<8;i++)
				{
					for(int j=0;j<8;j++)
						if(a[i][j]==1)
						System.out.print(" Q ");
						else
							System.out.print(" * ");
						System.out.println();
				}
							
				System.out.println();
				
			}
			else
			for(int i=0;i<8;i++)
			{
				if(a[start_line][i]==0)
				{
					a[start_line][i]=1;
					for(int x=i+1,y=start_line+1;y<8&&x<8;x++,y++)
						a[y][x]=a[y][x]+2;
					for(int x=i-1,y=start_line+1;y<8&&x>=0;x--,y++)
						a[y][x]=a[y][x]+2;
					for(int x=i,y=start_line+1;y<8;y++)
						a[y][x]=a[y][x]+2;
					
					f(a,start_line+1,counter);
					
					a[start_line][i]=0;
					for(int x=i+1,y=start_line+1;y<8&&x<8;x++,y++)
						a[y][x]=a[y][x]-2;
					for(int x=i-1,y=start_line+1;y<8&&x>=0;x--,y++)
						a[y][x]=a[y][x]-2;
					for(int x=i,y=start_line+1;y<8;y++)
						a[y][x]=a[y][x]-2;
					
				}
			}
		}
		


	
	/**
	 * @param args
	 */
	public static void main(String[] args) 
	{
		// TODO Auto-generated method stub
		//int taken=1;
		//int forbidden=2;
		int [][]a=new int [8][8];
		int []counter=new int[1];
		counter[0]=0;
		for(int i=0;i<8;i++)
			for(int j=0;j<8;j++)
				a[i][j]=0;
		
		f(a,0,counter);
	
	}

}