package 习题;

public class 八皇后 {
	static int c[] = new int[8];
	static int total = 0;
	public static void main(String[] args) {
		queen(0);
		System.out.println(total);

	}
	public static void queen(int row) {
		if(row==8) {   //找到一个解
			total++;
			/*for(int i=0;i<8;i++) 
				System.out.print(c[i]+" ");
			System.out.println();*/
		}
		else {
			for(int col = 0;col < 8;col++) {
				c[row] = col;
				if(isOk(row)) {
					queen(row+1);
				}
			}
		}
	}
	public static boolean isOk(int row) { //看看这一列能否放皇后
		for(int i = 0;i < row;i++) {
			if(c[row] == c[i] || row-c[row] == i-c[i] || row+c[row] == i+c[i]) { //列相同，对角线相同；对角线定律：行-列=行-列 或 行+列=行+列
				return false;
			}
		}
		return true;
	}
}