蛇形矩阵

import java.io.*;
import java.util.*;

public class Main{
    public static void main(String[] args) throws Exception{
        Scanner sc = new Scanner(System.in);
        while(sc.hasNextInt()){
            int num = sc.nextInt();

            int[][] dp = new int[num][num];

            int index = 1;

            for(int level = 1; level <= num; ++level){
                int i = level - 1;
                int j = 0;
                while((i >= 0) && (j <= level - 1)){
                    dp[i][j] = index;
                    i--;
                    j++;
                    index++;
                }
            }


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