Question

我编写了一个小程序，它基本上初始化了RandomPermutation1类型对象矩阵的单元格，所以它看起来像这样：

[1] [2] [3]

[4] [5] [6]

[7] [8] [0]

然后，方法shuffle（）会生成大量0的随机移动（假设为1000，但在我的情况下，甚至5不起作用）。

程序不会产生任何错误，但也不起作用（无限运行）。

如果有人能提出错误的提示，我将非常感激。

您可以在下面找到代码的MCTaRE（最小完整测试和可读示例）。

import java.util.*;

    public class RandomPermutation1{

      private int [][] randPerm;
      private int row, col;

      public RandomPermutation1(int row, int column){
        this.row = row;
        col = column;
        randPerm = new int[row][col];
        int number = 1;
        for (int i = 0; i < row; i++){
          for (int j = 0; j < col; j++){
            if (i == row - 1 && j == col - 1){
              randPerm[i][j] = 0;
            }
            else{
              randPerm[i][j] = number++;
            }
          }
        }
      }  

      public void shuffle(){

        int r = row-1;
        int c = col-1;
        int i = 0;

        while (i < 5){

          StringBuffer strB = new StringBuffer("");

          if (r > 0){strB.append("n");}
          if (r < row-1){strB.append("s");}
          if (c > 0){strB.append("w");}
          if (c < col-1){strB.append("e");}
          String s = getRandom(strB);
          switch(s){
            case "n":
              randPerm[r][c] = randPerm[r-1][c];
              randPerm[r-1][c] = 0;
              r = r-1;
              break;
            case "s":
              randPerm[r][c] = randPerm[r+1][c];
              randPerm[r+1][c] = 0;
              r = r+1;
              break;
            case "w":
              randPerm[r][c] = randPerm[r][c-1];
              randPerm[r][c-1] = 0;
              c = c-1;
              break;
            case "e":
              randPerm[r][c] = randPerm[r][c+1];
              randPerm[r][c+1] = 0;
              c = c+1;
              break;

          }
        }
        i++;
      }  

      private static String getRandom(StringBuffer strB) {    
        String str = strB.toString();
        int rnd = new Random().nextInt(str.length());
        return str.substring(rnd, rnd+1);
      }   


      public static void main (String[]args){
        RandomPermutation1 p = new RandomPermutation1 (3, 3);
        p.shuffle();    
      }  
    }

Answer 1

您需要将i++放入while循环

甚至更好

while (i++ < 5)

Java程序内存不足

1 个答案: