Java语言程序设计第7章编程练习题7.36八皇后

蛮力算法

public class eightQueens {
    public static void main(String[] args) {
        int[] queens = initial();
        while (check(queens))
            shake(queens);
        show(queens);
    }

    public static boolean check(int[] queens) {
        for (int i = 0; i < 8; i++)
            for (int j = 0; j < i; j++)
                if (Math.abs(i - j) == Math.abs(queens[i] - queens[j]))
                    return true;
        return false;
    }

    public static void shake(int[] queens) {
        int randomNum, temp, i;
        for (i = 0; i < 8; i++) {
            randomNum = (int) (Math.random() * 10000000) % 8;
            temp = queens[i];
            queens[i] = queens[randomNum];
            queens[randomNum] = temp;
        }
    }

    public static void show(int[] queens) {
        int i, j;
        for (i = 0; i < 8; i++) {
            for (j = 0; j < queens[i]; j++)
                System.out.print("| ");
            System.out.print("|Q");
            while (j++ + 1 < 8)
                System.out.print("| ");
            System.out.println('|');
        }
    }

    public static int[] initial() {
        int[] queens = new int[8];
        for (int i = 0; i < 8; i++)
            queens[i] = i;
        return queens;
    }
}