题解 | #蛇形矩阵#

import java.util.ArrayList;
import java.util.List;
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 scanner = new Scanner(System.in);
        int num = scanner.nextInt();
        shapeSnakeTriangle(num);
    }

    public static void shapeSnakeTriangle(int num) {
        List<Integer> next = new ArrayList<>();
        for (int j = num; j > 0; j--) {
            // 先得到 第一行的数据
            if (j == num) {
                int x = 0;
                for (int i = 1; i <= j; i++) {
                    x = x + i;
                    System.out.print(x);
                    System.out.print(" ");
                    if (i > 1) {
                        next.add(x - 1);
                    }
                }
                System.out.println();
            } else {
                List<Integer> temp = new ArrayList<>();
                for (int i = 0; i < next.size(); i++) {
                    System.out.print(next.get(i) + " ");
                    if (i > 0) {
                        temp.add(next.get(i) - 1);
                    }
                }
                System.out.println();
                next = temp;
            }


        }

    }
}