import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int get = in.nextInt();
        int[][] gets = new int[get][get];

        boolean isEnd = false;
        // 方向->右下左上0 1 2 3
        // 步数
        // 0 1 2 3 0
        // 3 2 2 1 1          2*3-1
        // 4 3 3 2 2 1 1      2*4-1
        // 5 3 3 2 2 1 1 0 0  2*5-1

        int direction = 0;
        int step = get;
        int nowR = 0;
        int nowH = 0;
        int start = 1;
        for (int i = 0; i < get * 2 - 1; i++) {
            for (int j = 1; j <= step; j++) {
                gets[nowR][nowH] = start;
                start++;
                if (j != step) {
                    if (direction == 0) {
                        nowH += 1;  // 右
                    } else if (direction == 1){
                        nowR += 1;  // 下
                    } else if (direction == 2) {
                        nowH -= 1;  // 左
                    } else if (direction == 3) {
                        nowR -= 1;  // 上
                    }
                }
            }

            if (direction == 3) direction = 0;
            else direction += 1;
            if (direction == 0) {
                nowH += 1;  // 右
            } else if (direction == 1){
                nowR += 1;  // 下
            } else if (direction == 2) {
                nowH -= 1;  // 左
            } else if (direction == 3) {
                nowR -= 1;  // 上
            }

            if (i % 2 == 0) {
                step -= 1;
            }

        }

        for (int i = 0; i < get; i++) {
            for (int j = 0; j < get; j++) {
                System.out.print(gets[i][j] + " ");
            }
            System.out.println();
        }
    }
}

没看懂的，欢迎咨询。