题解 | #蛇形矩阵#

采用等差数列解决即可,特别注意:        for (int j = 0; j < a - i; j++) {               System.out.print(heng);               heng = heng + 2 + i + j;               System.out.print(" ");           }

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);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int a = in.nextInt();
            int startNum = 1;
            for (int i = 0; i < a; i++) {
                int heng = startNum;
                for (int j = 0; j < a - i; j++) {
                    System.out.print(heng);
                    heng = heng + 2 + i + j;
                    System.out.print(" ");
                }
                startNum = i + 1 + startNum;
                System.out.println();
            }
        }
    }
}