八皇后问题

笨蛋一个，做了一天多才做出来，还是有提示的情况下。。。。下面是我的代码

package com.www.demo06;


public class Queen8 {
    int sum = 0;//总共多少方法
    int num = 1;//下的棋子个数

    int[] arr = new int[8];//记录哪个位置落下棋子了，arr[i]中的i表示行，值表示列

    public void initialQueen(){
        for (int i = 0;i < 8;i++){
            queen(0,i);
        }
        System.out.println(sum);
    }

    public void queen(int x,int y){//皇后位置（x,y）
        //第一步-----限制条件：走通返回路径，没走通循环下一个可走路径
        arr[x] = y;//第x行第y列放皇后
        if (num == 8){
            for (int i = 0;i < 8;i++){
                System.out.print("(" + i + "," + arr[i] + ")");
            }
            System.out.println();
            sum++;
            return;
        }
        //第二步
        for (int j = 0;j < 8;j++){//下一个棋子可能放的列数
            //对于每一列都进行判断
            num++;
            int i = 0;
            while (i <= x) {
                //对列数进行限制：判断完所有限制之后，可以下棋
                //对于第x+1行第j列，如果前面的x行对其限制有用，跳出循环看下一列，如果没用，进入递归
                if (j == arr[i] - x - 1 + i|| j == arr[i] || j == arr[i] + x + 1 -i){//竖和斜线
                    break;
                }
                if (i == x){
                    queen(x + 1,j);
                }
                i++;
            }
            num--;//执行结束，恢复棋子个数，继续下一个可以下棋的列
        }//假如每一列都不符合要求，就返回上一个的循环
    }
    
}

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输出结果如下：
(0,0)(1,4)(2,7)(3,5)(4,2)(5,6)(6,1)(7,3)
(0,0)(1,5)(2,7)(3,2)(4,6)(5,3)(6,1)(7,4)
(0,0)(1,6)(2,3)(3,5)(4,7)(5,1)(6,4)(7,2)
(0,0)(1,6)(2,4)(3,7)(4,1)(5,3)(6,5)(7,2)
(0,1)(1,3)(2,5)(3,7)(4,2)(5,0)(6,6)(7,4)
(0,1)(1,4)(2,6)(3,0)(4,2)(5,7)(6,5)(7,3)
(0,1)(1,4)(2,6)(3,3)(4,0)(5,7)(6,5)(7,2)
(0,1)(1,5)(2,0)(3,6)(4,3)(5,7)(6,2)(7,4)
(0,1)(1,5)(2,7)(3,2)(4,0)(5,3)(6,6)(7,4)
(0,1)(1,6)(2,2)(3,5)(4,7)(5,4)(6,0)(7,3)
(0,1)(1,6)(2,4)(3,7)(4,0)(5,3)(6,5)(7,2)
(0,1)(1,7)(2,5)(3,0)(4,2)(5,4)(6,6)(7,3)
(0,2)(1,0)(2,6)(3,4)(4,7)(5,1)(6,3)(7,5)
(0,2)(1,4)(2,1)(3,7)(4,0)(5,6)(6,3)(7,5)
(0,2)(1,4)(2,1)(3,7)(4,5)(5,3)(6,6)(7,0)
(0,2)(1,4)(2,6)(3,0)(4,3)(5,1)(6,7)(7,5)
(0,2)(1,4)(2,7)(3,3)(4,0)(5,6)(6,1)(7,5)
(0,2)(1,5)(2,1)(3,4)(4,7)(5,0)(6,6)(7,3)
(0,2)(1,5)(2,1)(3,6)(4,0)(5,3)(6,7)(7,4)
(0,2)(1,5)(2,1)(3,6)(4,4)(5,0)(6,7)(7,3)
(0,2)(1,5)(2,3)(3,0)(4,7)(5,4)(6,6)(7,1)
(0,2)(1,5)(2,3)(3,1)(4,7)(5,4)(6,6)(7,0)
(0,2)(1,5)(2,7)(3,0)(4,3)(5,6)(6,4)(7,1)
(0,2)(1,5)(2,7)(3,0)(4,4)(5,6)(6,1)(7,3)
(0,2)(1,5)(2,7)(3,1)(4,3)(5,0)(6,6)(7,4)
(0,2)(1,6)(2,1)(3,7)(4,4)(5,0)(6,3)(7,5)
(0,2)(1,6)(2,1)(3,7)(4,5)(5,3)(6,0)(7,4)
(0,2)(1,7)(2,3)(3,6)(4,0)(5,5)(6,1)(7,4)
(0,3)(1,0)(2,4)(3,7)(4,1)(5,6)(6,2)(7,5)
(0,3)(1,0)(2,4)(3,7)(4,5)(5,2)(6,6)(7,1)
(0,3)(1,1)(2,4)(3,7)(4,5)(5,0)(6,2)(7,6)
(0,3)(1,1)(2,6)(3,2)(4,5)(5,7)(6,0)(7,4)
(0,3)(1,1)(2,6)(3,2)(4,5)(5,7)(6,4)(7,0)
(0,3)(1,1)(2,6)(3,4)(4,0)(5,7)(6,5)(7,2)
(0,3)(1,1)(2,7)(3,4)(4,6)(5,0)(6,2)(7,5)
(0,3)(1,1)(2,7)(3,5)(4,0)(5,2)(6,4)(7,6)
(0,3)(1,5)(2,0)(3,4)(4,1)(5,7)(6,2)(7,6)
(0,3)(1,5)(2,7)(3,1)(4,6)(5,0)(6,2)(7,4)
(0,3)(1,5)(2,7)(3,2)(4,0)(5,6)(6,4)(7,1)
(0,3)(1,6)(2,0)(3,7)(4,4)(5,1)(6,5)(7,2)
(0,3)(1,6)(2,2)(3,7)(4,1)(5,4)(6,0)(7,5)
(0,3)(1,6)(2,4)(3,1)(4,5)(5,0)(6,2)(7,7)
(0,3)(1,6)(2,4)(3,2)(4,0)(5,5)(6,7)(7,1)
(0,3)(1,7)(2,0)(3,2)(4,5)(5,1)(6,6)(7,4)
(0,3)(1,7)(2,0)(3,4)(4,6)(5,1)(6,5)(7,2)
(0,3)(1,7)(2,4)(3,2)(4,0)(5,6)(6,1)(7,5)
(0,4)(1,0)(2,3)(3,5)(4,7)(5,1)(6,6)(7,2)
(0,4)(1,0)(2,7)(3,3)(4,1)(5,6)(6,2)(7,5)
(0,4)(1,0)(2,7)(3,5)(4,2)(5,6)(6,1)(7,3)
(0,4)(1,1)(2,3)(3,5)(4,7)(5,2)(6,0)(7,6)
(0,4)(1,1)(2,3)(3,6)(4,2)(5,7)(6,5)(7,0)
(0,4)(1,1)(2,5)(3,0)(4,6)(5,3)(6,7)(7,2)
(0,4)(1,1)(2,7)(3,0)(4,3)(5,6)(6,2)(7,5)
(0,4)(1,2)(2,0)(3,5)(4,7)(5,1)(6,3)(7,6)
(0,4)(1,2)(2,0)(3,6)(4,1)(5,7)(6,5)(7,3)
(0,4)(1,2)(2,7)(3,3)(4,6)(5,0)(6,5)(7,1)
(0,4)(1,6)(2,0)(3,2)(4,7)(5,5)(6,3)(7,1)
(0,4)(1,6)(2,0)(3,3)(4,1)(5,7)(6,5)(7,2)
(0,4)(1,6)(2,1)(3,3)(4,7)(5,0)(6,2)(7,5)
(0,4)(1,6)(2,1)(3,5)(4,2)(5,0)(6,3)(7,7)
(0,4)(1,6)(2,1)(3,5)(4,2)(5,0)(6,7)(7,3)
(0,4)(1,6)(2,3)(3,0)(4,2)(5,7)(6,5)(7,1)
(0,4)(1,7)(2,3)(3,0)(4,2)(5,5)(6,1)(7,6)
(0,4)(1,7)(2,3)(3,0)(4,6)(5,1)(6,5)(7,2)
(0,5)(1,0)(2,4)(3,1)(4,7)(5,2)(6,6)(7,3)
(0,5)(1,1)(2,6)(3,0)(4,2)(5,4)(6,7)(7,3)
(0,5)(1,1)(2,6)(3,0)(4,3)(5,7)(6,4)(7,2)
(0,5)(1,2)(2,0)(3,6)(4,4)(5,7)(6,1)(7,3)
(0,5)(1,2)(2,0)(3,7)(4,3)(5,1)(6,6)(7,4)
(0,5)(1,2)(2,0)(3,7)(4,4)(5,1)(6,3)(7,6)
(0,5)(1,2)(2,4)(3,6)(4,0)(5,3)(6,1)(7,7)
(0,5)(1,2)(2,4)(3,7)(4,0)(5,3)(6,1)(7,6)
(0,5)(1,2)(2,6)(3,1)(4,3)(5,7)(6,0)(7,4)
(0,5)(1,2)(2,6)(3,1)(4,7)(5,4)(6,0)(7,3)
(0,5)(1,2)(2,6)(3,3)(4,0)(5,7)(6,1)(7,4)
(0,5)(1,3)(2,0)(3,4)(4,7)(5,1)(6,6)(7,2)
(0,5)(1,3)(2,1)(3,7)(4,4)(5,6)(6,0)(7,2)
(0,5)(1,3)(2,6)(3,0)(4,2)(5,4)(6,1)(7,7)
(0,5)(1,3)(2,6)(3,0)(4,7)(5,1)(6,4)(7,2)
(0,5)(1,7)(2,1)(3,3)(4,0)(5,6)(6,4)(7,2)
(0,6)(1,0)(2,2)(3,7)(4,5)(5,3)(6,1)(7,4)
(0,6)(1,1)(2,3)(3,0)(4,7)(5,4)(6,2)(7,5)
(0,6)(1,1)(2,5)(3,2)(4,0)(5,3)(6,7)(7,4)
(0,6)(1,2)(2,0)(3,5)(4,7)(5,4)(6,1)(7,3)
(0,6)(1,2)(2,7)(3,1)(4,4)(5,0)(6,5)(7,3)
(0,6)(1,3)(2,1)(3,4)(4,7)(5,0)(6,2)(7,5)
(0,6)(1,3)(2,1)(3,7)(4,5)(5,0)(6,2)(7,4)
(0,6)(1,4)(2,2)(3,0)(4,5)(5,7)(6,1)(7,3)
(0,7)(1,1)(2,3)(3,0)(4,6)(5,4)(6,2)(7,5)
(0,7)(1,1)(2,4)(3,2)(4,0)(5,6)(6,3)(7,5)
(0,7)(1,2)(2,0)(3,5)(4,1)(5,4)(6,6)(7,3)
(0,7)(1,3)(2,0)(3,2)(4,5)(5,1)(6,6)(7,4)
92