题解 | #蛇形矩阵#

import java.util.Scanner;

// 查看备注即可
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int sum = 0;
        int[][] a = new int[n][n];
        int count = 1; // 数组的值
        int x = 0;
        int y = 0;
        a[0][0] = 1;
//        for (int k = 0; k < 3; k++) {
        while (count < n * n) {
            if (y < n - 1) {
                y++;
                // 向右赋值 x不变 y变
                if (a[x][y] == 0) {
                    a[x][y] = ++count;
                }
//                 System.out.println("向右赋值：" + count + ":" + x + "," + y);
            } else {
                // 向下赋值
                x++;
                if (a[x][y] == 0) {
                    a[x][y] = ++count;
                }
//                 System.out.println("向下赋值：" + count + ":" + x + "," + y);
            }
            // 向左下角赋值
            if (x < n - 1 && y > 0) {
                int numy = y;
                int numx = x;
                for (int i = 0; i < Math.abs(numx - numy); i++) {
                    x++;
                    y--;
                    if (a[x][y] == 0) {
                        a[x][y] = ++count;
                    }
//                     System.out.println("向左下角赋值：" + count + ":" + x + "," + y);
                }
            }

            if (x < n - 1) {
                // 向下赋值
                x++;
                if (a[x][y] == 0) {
                    a[x][y] = ++count;
                }
//                 System.out.println("向下赋值：" + count + ":" + x + "," + y);
            } else {
                y++;
                // 向右赋值 x不变 y变
                if (a[x][y] == 0) {
                    a[x][y] = ++count;
                }
//                 System.out.println("向右赋值：" + count + ":" + x + "," + y);
            }

            // 右上角赋值
            if (x > 0 && y < n - 1) {
                int numy = y;
                int numx = x;
                for (int i = 0; i < Math.abs(numx - numy); i++) {
                    x--;
                    y++;
                    if (a[x][y] == 0) {
                        a[x][y] = ++count;
                    }
//                     System.out.println("右上角赋值：" + count + ":" + x + "," + y);
                }
            }

        }
        // 打印出数组
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < a[i].length; j++) {
                System.out.print(a[i][j] + " ");
            }
            System.out.println();
        }
    }
}