java实现Z字形扫描程序

import java.util.Scanner;
 
public class Main {
 
 // 方向枚举
 enum Direction{
 DOWN, RIGHT_UP, RIGHT, LEFT_DOWN
 }
 
 public static void main(String[] args) {
 // TODO Auto-generated method stub
 int N, M;
 int[][] a;
 
 Scanner scan = new Scanner(System.in);
 N = scan.nextInt(); 
 M = scan.nextInt();
 
 a = new int[N][M];
 for(int i = 0; i < N; i++) {
 for(int j = 0; j < M; j++) {
 a[i][j] = scan.nextInt();
 }
 }
 
 int row = 0, col = 0;
 Direction dir = Direction.DOWN;
 System.out.print(a[row][col] + " ");
 
 
 while(!(row == N - 1 && col == M - 1)) {
 
 switch(dir) {
 case DOWN: // 向下走
  if(row < N - 1) {
  row++;
  System.out.print(a[row][col] + " ");
  if(col != M - 1) {
  dir = Direction.RIGHT_UP;
  } else {
  dir = Direction.LEFT_DOWN;
  }
  } else {
  dir = Direction.RIGHT;
  }
  break;
 case RIGHT_UP: // 向右上方向走
  while(row > 0 && col < M - 1) {
  row--;
  col++;
  System.out.print(a[row][col] + " ");
  }
  
  if(row != 0) {
  dir = Direction.DOWN;
  } else {
  dir = Direction.RIGHT;
  }
  
  break;
 case RIGHT: // 向右走
  if(col < M - 1) {
  col++;
  System.out.print(a[row][col] + " ");
  if(row != N - 1) {
  dir = Direction.LEFT_DOWN;
  } else {
  dir = Direction.RIGHT_UP;
  }
  } else {
  dir = Direction.DOWN;
  }
  
  break;
 case LEFT_DOWN: // 向左下方向走
  while(col > 0 && row < N - 1) {
  row++;
  col--;
  System.out.print(a[row][col] + " ");
  } 
  
  if(col != 0) {
  dir = Direction.DOWN;
  } else {
  dir = Direction.RIGHT;
  }
  
  break;
 }
 
 }
 
 
 }
 
 
}