mazemodel.java

一个迷宫的JAVA程序

import java.util.*;

public class MazeModel extends Object {
  static private int NORTH=0,SOUTH=1,EAST=2,WEST=3,FAILED=4;
  static private int ROW_MAX=15, COL_MAX=30;
  private char[][] maze;
  private int startRow, startCol;
  private MazeView view;

  private class ChoicePoint extends Object {
    private int row, col, direction;
    private ChoicePoint(int row, int col, int direction) {// constructor
      this.row = row; this.col = col; this.direction = direction; }
    public int getDirection() { return direction; }
    public int getRow() { return row; }
    public int getCol() { return col; }
  }

  public MazeModel(MazeView mv) { // constructor MazeView mv
    view = mv;
    maze = new char[ROW_MAX][COL_MAX];
    initMaze();
  }    

  public void initMaze() {
    for(int row=0; row < ROW_MAX; row++)
      for(int col=0; col < COL_MAX; col++)
        maze[row][col] = '*';
  }

  private void findStartPos() {
    for(int row=0; row < ROW_MAX; row++)
      for(int col=0; col < COL_MAX; col++)
        if (maze[row][col] == 'P')
          { startRow = row; startCol = col; return; }
  }

  public boolean solveMaze(){
    findStartPos();
    maze[startRow][startCol] = '*';
    boolean solved = getOut();
    maze[startRow][startCol] = 'P';
    view.printMaze();
    return solved;
  }

  public boolean getOut(){
    Stack s = new Stack();
    ChoicePoint c;
    int currDir = -1;
    int currRow, currCol, newRow, newCol;
    c = new ChoicePoint(startRow, startCol, currDir);
    s.push(c);

    while(s.size() > 0) { // while1
      c = (ChoicePoint) s.pop();
      currDir = c.getDirection();
      currRow = c.getRow();
      currCol = c.getCol();
      while(currDir != FAILED) {   // while2
        if (currDir == NORTH)
           { newRow = currRow - 1; newCol = currCol; }
        else if (currDir == SOUTH)
           { newRow = currRow + 1; newCol = currCol; }
        else if (currDir == EAST)
           { newRow = currRow; newCol = currCol + 1; }
        else if (currDir == WEST)
           { newRow = currRow; newCol = currCol - 1; }
        else 
           { currDir += 1; continue; }

        if (maze[newRow][newCol] == 'T')
           return true;
        else
           if (maze[newRow][newCol] == ' ') {
              maze[newRow][newCol] = '.';
              s.push(new ChoicePoint(currRow,currCol,currDir));
	      currRow = newRow;
	      currCol = newCol;             
	      currDir = NORTH;  }
           else 
              currDir += 1;          
     } // end of while2, next step should be in backtrace
     maze[currRow][currCol]='A';  // new add  
    }// end of while1
    return false;
  }
    
  // the following methods are called from MazeView.java

  public void setMaze(String mazeStr) {
    for(int row=0; row < ROW_MAX; row++)
      {
       int strPos = row * COL_MAX + row;
       for( int col = 0; col < COL_MAX; col++)
         {
          maze[row][col] = mazeStr.charAt(strPos);
          strPos++;
         }
       strPos++; 
      }
  }
   
  public String getMaze() {
    String str = "";
    for(int row=0; row < ROW_MAX; row++)
      {
       for( int col = 0; col < COL_MAX; col++) 
           str = str + maze[row][col];
       str = str + "\n";                         
      }
    return str;
  }

  public String getResult() {
    String str = "";
    for(int row=0; row < ROW_MAX; row++)
      {
       for( int col = 0; col < COL_MAX; col++) {
          if (maze[row][col]=='A')
             maze[row][col]=' ';
           str = str + maze[row][col];
       }      
       str = str + "\n";                         
      }
    return str;
  }

}