Labyrinth

Labyrinth.java

/**
 * Assignment 9, exercise 3
 * Class representing a labyrinth
 * Two constructors are already implemented, also a method to print out the labyrinth and its solution
 *
 * @author Lisa Julia Nebel Julius Plenz
 */
 // TODO Take a look how this class works. 
 // TODO Look at the docstrings, document your own functions
 
 // TODO Implement two functions to solve the Labyrinth. You will find the stubs below
 //		 (solve and solveRightHandRule)
 
 // TODO Implement the third constructor that generates a labyrinth with given size and given probability
 // test the solvability of 1000 labyrinths of size 10 by 10 with the parameters p=0.8 and p=0.9
 // (p stands for the probability of any entry in the matrix being 1)

public class Labyrinth{
	int[][] labyrinth; // labyrinth as defined in the assignment
	int[][] solution; // solution to the labyrinth
	Boolean solved; // Is the labyrinth already solved?
	
	/**
     * Construct a Labyrinth with default size
	 */
	public Labyrinth(){
		this.labyrinth=makeRandomLabyrinth(4,0.8);
		this.solved=false;
	}
	
	/**
     * Construct a Labyrinth with given size and given "1"-probability
	 * Not yet implemented!
	 */
	public Labyrinth(int size, double p){
		this.labyrinth = makeRandomLabyrinth(size,p);
	}
	
	public Labyrinth(int[][]labyrinth){
		this.labyrinth=labyrinth; 
		this.solved=false;
	}
	
    /**
     * @param labyrinth size and probability for "1"
	 *
	 * @return a labyrinth (int[][])
	 */
	public static int[][] makeRandomLabyrinth(int size, double p){
		int[][] labyrinth=new int[size][size];
		for (int i1=0; i1<size; i1++) {
			for (int i2=0; i2<size; i2++) {
				double r = Math.random();
				labyrinth[i1][i2]=r<p?1:0; //Question: If r<p, then [i1][i2] = 1, else: then [i1][i2] = 0
			}
		}
		return labyrinth;
    }
	
	/**
	 * Prints out the Labyrinth and its solution, if possible!
	 */
	public void printLabyrinth(){ //
		for (int i1=0; i1<this.labyrinth.length; i1++) {
			for (int i2=0; i2<this.labyrinth[i1].length; i2++) {
				System.out.print(this.labyrinth[i1][i2]);
			}
			System.out.println();
		}
		System.out.println();
		if(this.solved){
			for (int i1=0; i1<this.labyrinth.length; i1++) {
				for (int i2=0; i2<this.labyrinth[i1].length; i2++) {
					System.out.print(this.solution[i1][i2]);
				}
				System.out.println();
			}
		}
		
	}
	
	public boolean solve(){ //Solve the labyrinth. Return true if the labyrinth is solvable, otherwise return false. change the solution attribute to the solution.
		this.labyrinth = labyrinth;
		if (labyrinth[0][0]==1){
			int i1 = 0;
			int i2 = 0;
			if (i1!= (this.labyrinth.length-1) && i2!=(this.labyrinth.length-1)){
					if (labyrinth[i1-1][i2]==1 && i1>0){
						labyrinth[i1-1][i2]=8;
						i1 = i1-1;
					}
					else if (labyrinth[i1+1][i2]==1 && (i1+1)<this.labyrinth.length){
						labyrinth[i1+1][i2]=8;
						i1 = i1+1;
					}
					else if (labyrinth[i1][i2-1]==1 && i2>0){
						labyrinth[i1][i2-1]=8;
						i2 = i2-1;
					}
					else if (labyrinth[i1][i2+1]==1 && (i2+1)<this.labyrinth.length){
						labyrinth[i1][i2+1]=8;
						i2 = i2+1;
					}
					else {
						labyrinth[i1][i2]=0;
						
						if (labyrinth[i1-1][i2]==8 && i1>0){
							i1 = i1-1;
						}
						else if (labyrinth[i1+1][i2]==8 && (i1+1)<this.labyrinth.length){
							i1 = i1+1;
						}
						else if (labyrinth[i1][i2-1]==8 && i2>0){
							i2 = i2-1;
						}
						else if (labyrinth[i1][i2+1]==8 && (i2+1)<this.labyrinth.length){
							i2 = i2+1;
						}
						
					}
					
					}
				}
		return false;
	}
	
	public boolean solveRightHandRule(){ //implement the right-hand-rule explained in the assignment		
		
		return false;
	}
	
	public static void main(String args[]){
	
		System.out.println("Aufgabe 3a:");
		int[][] testLab={{1,0,1,1},{1,1,1,1},{0,1,0,1},{0,1,0,1}};
		Labyrinth L1=new Labyrinth(testLab);
		L1.solve();
		L1.printLabyrinth();
		Labyrinth L2=new Labyrinth();
		L2.solve();
		L2.printLabyrinth();
		
		System.out.println("Aufgabe 3b:");
		Labyrinth L3=new Labyrinth(testLab);
		L3.solveRightHandRule();
		L3.printLabyrinth();
		
		
	}
}

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1
at Labyrinth.solve(Labyrinth.java:88)
at Labyrinth.main(Labyrinth.java:137)