题解 | #蛇形矩阵#

import java.util.*;

// 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);
        in.useDelimiter("\n");
        int s1 = 0;
        // 注意 hasNext 和 hasNextLine 的区别
        if (in.hasNextInt()) { // 注意 while 处理多个 case
            s1 = in.nextInt();
        }
        if (s1 <= 0) {
            return;
        }
        int[][] res = new int[s1][s1];
	    //第一列
        res[0][0] = 1;
        for (int i = 1, column = 1; i < res.length; i++, column++) {
            res[i][0] = res[i - 1][0] + column;
        }
	    //余下几列，按行写入
        for (int i = 0, rowInit = 2; i < res.length; i++, rowInit++, s1--) {
            for (int j = 1, row = rowInit; j < s1; j++, row++) {
                res[i][j] = res[i][j - 1] + row;
            }
        }
    	//输出
        for (int i = 0; i < res.length; i++) {
            for (int j = 0; j < res.length; j++) {
                if (res[i][j] != 0) {
                    System.out.print(res[i][j] + " ");
                }
            }
            System.out.println();
        }

    }
}