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MazeSolver.java
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MazeSolver.java
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package com.company;
import java.awt.*;
import java.util.*;
import java.math.*;
import java.io.*;
import java.util.Arrays;
import java.util.Locale;
interface IQueue {
/*** Inserts an item at the queue front.*/
public void enqueue(Object item);
/*** Removes the object at the queue rear and returnsit.*/
public Object dequeue();
/*** Tests if this queue is empty.*/
public boolean isEmpty();
/*** Returns the number of elements in the queue*/
public int size();
}
interface ILinkedList {
public void add(int index, Object element);
public void add(Object element);
public Object get(int index);
public void set(int index, Object element);
public void clear();
public boolean isEmpty();
public void remove(int index);
public int size();
public void sublist(int fromIndex, int toIndex);
public boolean contains(Object o);
}
class DoublyLinkedList implements ILinkedList{
class node {
public Object elm ;
node next ;
node prev ;
}
int size=0;
node head=null;
node tail=null;
// public static int size=0;
node pointer;
public void add(Object element){ //*same as single*//
if(size==0){
node no =new node();
no.elm=element;
no.next=null;
no.prev=null;
head=no;
tail=no;
size++;
}
else{
node f=new node();
f.elm=element;
tail.next=f;
f.prev=tail;
tail=f;
tail.next=null;
size++;
}
pointer = head;
}
public void print(){ //*same as single*//
node p=tail;
System.out.print("[");
for(int i=size()-1;i>=0;i--){
System.out.print(p.elm);
p=p.prev;
if(i != 0)
System.out.print(", ");
}
System.out.print("]");
}
public void add(int index, Object element)
{
node added = new node();
added.elm = element;
if(size == 0)
{
added.next = null;
added.prev = null;
head = added;
tail = added;
}
else {
node counter;
if(index <= size/2) {
counter = head;
for (int i = 0; i < index - 1; i++)
counter = counter.next; // stopped right before the required index
}
else
{
counter = tail;
// stopped right before the req index to make it similar the manupilation uphere
for(int i = 0; i < size - index; i++)
counter = counter.prev;
}
if(index!=0) {
added.next = counter.next;
added.prev = counter;
counter.next.prev = added;
counter.next = added;
}
else
{
added.next = head;
head = added;
head.prev = null;
}
}
size++;
}
public Object get(int index){
node count = head;
if(index<=size){
for(int j=0;j<size;j++){
if(j==index){
return count.elm;
}
count=count.next;
}
}
return ("null");
}
public void set(int index, Object element){
node counter;
if(index <= size/2)
{
counter = head;
for (int i = 0; i < index; i++)
counter = counter.next;
counter.elm = element;
}
else
{
counter = tail;
for (int i = 0; i < size - index - 1; i++)
counter = counter.prev;
counter.elm = element;
}
return ;
}
public void clear(){ //*same as single*//
node x=null;
head=x;
tail=x;
size=0;
return ;}
public boolean isEmpty(){if(size==0)return true; //*same as single*//
else return false;
}
public void remove(int index) {
if(index != 0 && index != size-1){
node counter;
if (index <= size / 2) {
counter = head;
for (int i = 0; i < index - 1; i++)
counter = counter.next; // To stop just after the removed node
// Erga3 mrten w 5alli elly 2odamak elle m3ana
counter.next = counter.next.next;
} else {
counter = tail;
for (int i = 0; i < size - index ; i++)
counter = counter.prev; // To stop just before the removed node
counter.next = counter.next.next;
// It could be done with prev,
// for clarity we chosed same approach
// of single linked list
}
}
else if(index == 0)
head = head.next; // Feha 7aga me4 tmam
else if(index == size-1)
tail = tail.prev;
if(size == 1)
{
head = tail = null;
}
size--;
return;
}
public int size(){return size;} //*same as single*//
public void sublist(int fromIndex, int toIndex){
node counter = head;
System.out.print("[");
for(int i = 0; i < size; i++)
{
if(i >= fromIndex && i <= toIndex)
{
System.out.print(counter.elm);
if(i != toIndex)
System.out.print(", ");
}
counter = counter.next;
}
System.out.print("]");
return ;
}
public boolean contains(Object o){
if(head != null) {
node contain = head;
for (int j = 0; j < size; j++) {
if (contain.elm == o) {
return true;
}
contain = contain.next;
}
}
return false;
}
}
interface IStack {
/*** Removes the element at the top of stack and returnsthat element.
* @return top of stack element, or through exception if empty
*/
public Object pop();
/*** Get the element at the top of stack without removing it from stack.
* @return top of stack element, or through exception if empty
*/
public Object peek();
/*** Pushes an item onto the top of this stack.
* @return object to insert*
*/
public void push(Object element);
/*** Tests if this stack is empty
* @return true if stack empty
*/
public boolean isEmpty();
public int size();
}
class MyStack implements IStack {
class Node {
Object data;
Node next;
}
Node head = null;
public void add(Object element) {
Node current = new Node();
current.data = element;
current.next = null;
Node temp = head;
if (head == null)
head = current;
else {
while (temp.next != null) {
temp = temp.next;
}
temp.next = current;
}
}
public void display() {
Node current = head;
System.out.print("[");
for (int i = 0; current != null; ++i) {
System.out.print(current.data);
if (current.next != null)
System.out.print(", ");
current = current.next;
}
System.out.print("]");
}
public void push(Object element) {
Node current = new Node();
current.data = element;
current.next = head;
head = current;
}
public Object pop() {
if (head == null) {
System.out.println("Error");
System.exit(0);
}
Object obj = head.data;
head = head.next;
return obj;
}
public Object peek() {
if (head == null) {
System.out.println("Error");
System.exit(0);
}
return head.data;
}
public boolean isEmpty() {
if (head == null)
return true;
return false;
}
public int size() {
Node current = new Node();
int size = 0;
if (head == null)
return size;
current = head;
while (current != null) {
size++;
current = current.next;
}
return size;
}
}
class LinkedListQueue implements IQueue {
static DoublyLinkedList dbl = new DoublyLinkedList();
static LinkedListQueue Q = new LinkedListQueue();
public void enqueue(Object item) {
dbl.add(item);
}
public Object dequeue() {
dbl.pointer = dbl.head;
dbl.remove(0);
return dbl.pointer.elm;
}
public boolean isEmpty() {
return dbl.isEmpty();
}
public int size() {
return dbl.size();
}
}
interface IMazeSolver {
/**
* Read the maze file, and solve it using Breadth First Search
* @param maze maze file
* @return the coordinates of the found path from point ’S’
*
to point ’E’ inclusive, or null if no path is found.
*/
public int[][] solveBFS(java.io.File maze) throws FileNotFoundException;
/**
* Read the maze file, and solve it using Depth First Search
* @param maze maze file
* @return the coordinates of the found path from point ’S’
*
to point ’E’ inclusive, or null if no path is found.
*/
public int[][] solveDFS(java.io.File maze) throws FileNotFoundException;
}
public class MazeSolver implements IMazeSolver{
LinkedListQueue Q = new LinkedListQueue();
public int[][] solveBFS(java.io.File maze) throws FileNotFoundException {
int[][] error = new int[2][1];
error[0][0] = -1; error[1][0] = -1;
Scanner in = new Scanner(maze);
String[] s = in.nextLine().split(" ");
int N = Integer.parseInt(s[0]), M = Integer.parseInt(s[1]);
char[][] arr = new char[N][M];
for (int i = 0; in.hasNextLine(); i++) {
arr[i] = in.nextLine().toCharArray();
}
String root = "haha";
String hold = "hehe"; String[] held;
int[][] answer= new int[100][2];
String[][] parents = new String[M][N];
Boolean [][]visited = new Boolean[M][N];
for(int i = 0; i < M; i++){
for (int j = 0; j < N; j++)
visited[i][j] = false;
}
for(int i = 0; i < M; i++){
for(int j = 0; j < N; j++){
if(arr[i][j]=='S') {
root = i + "," + j;
parents[i][j] = -1+","+-1;
break;
}
}
}
if(root.equals("haha")) return error;
else {
Q.enqueue(root);
String tank;
boolean found = false; // for the E
int i, j, k, m = -1, n = -1, x = -1, y = -1;
while (!Q.isEmpty()&&!found) {
hold = String.valueOf(Q.dequeue());
held = hold.split(",");
//visited part
i = Integer.parseInt(held[0]);
j = Integer.parseInt(held[1]);
visited[i][j] = true;
for (k = 0; k < 4; k++) {
if (k == 0) {
m = i;
n = j - 1;
}//check left
else if (k == 1) {
m = i;
n = j + 1;
}//check right
else if (k == 2) {
m = i - 1;
n = j;
}//check up
else if (k == 3) {
m = i + 1;
n = j;
}
if (n < 0 || m < 0 || n >= N || m >= M || arr[i][j] == '#' || visited[m][n]) {
}else if (arr[m][n] == '.') {
tank = m + "," + n;
Q.enqueue(tank);
parents[m][n] = i + "," + j;
} else if (arr[m][n] == 'E') {
x = m;
y = n;
parents[m][n] = i + "," + j;
answer[0][0]=m;answer[0][1]=n;
//System.out.println("{"+m+","+n+"}");
while (!Q.isEmpty())
Q.dequeue();
found = true;
}
}
}
if (x == -7 || y == -7)
return error;
else{
String[] tenk = new String[2];
tank = parents[x][y]; int r = 1;
tenk = tank.split(",");
x = Integer.parseInt(tenk[0]);
y = Integer.parseInt(tenk[1]);
while (!tank.equals("-1,-1")) {
answer[r][0] = x; answer[r][1] = y; r++;
//System.out.println("{" + tank + "}");
tank = parents[x][y];
tenk = tank.split(",");
x = Integer.parseInt(tenk[0]);
y = Integer.parseInt(tenk[1]);
}
int[][] bfs = new int[r][2];
for(int w = 0; w < r; w++){
bfs[r-w-1][0] = answer[w][0];
bfs[r-w-1][1] = answer[w][1];
}
return(bfs);
}
}
}
public int[][] solveDFS(java.io.File maze) throws FileNotFoundException {
// handle the input
Scanner in = new Scanner(maze);
String[] s = in.nextLine().split(" ");
int n = Integer.parseInt(s[0]), m = Integer.parseInt(s[1]);
char[][] grid = new char[n][m];
for (int i = 0; in.hasNextLine(); i++)
grid[i] = in.nextLine().toCharArray();
// get the start point which we will start from it
int x=0,y=0;
boolean found=false; //this variable found made to break when we found the start point
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if(grid[i][j]=='S'){
x=i;
y=j;
found=true;
break;
}
}
if(found)break;
}
Point p=new Point(x,y); //create the start point
MyStack stack =new MyStack();
stack.push(p);
while (true){ /* we get the point and change this position in the grid to #
as not to return to this point again
*/
x=((Point)stack.peek()).x;
y=((Point)stack.peek()).y;
grid[x][y]='#';
//check down
if(x+1<n) {
if(grid[x + 1][y] == 'E'){
stack.push(new Point(x+1,y));
break;
}
else if (grid[x + 1][y] == '.') {
stack.push(new Point(x+1,y));
continue;
}
}
//check left
if(y-1>=0) {
if(grid[x][y-1] == 'E'){
stack.push(new Point(x,y-1));
break;
}
else if (grid[x][y - 1] == '.') {
stack.push(new Point(x,y-1));
continue;
}
}
//check up
if(x-1>=0) {
if(grid[x - 1][y] == 'E'){
stack.push(new Point(x-1,y));
break;
}
else if (grid[x - 1][y] == '.') {
stack.push(new Point(x-1,y));
continue;
}
}
//check right
if(y+1<m) {
if(grid[x][y+1] == 'E'){
stack.push(new Point(x,y+1));
break;
}
if (grid[x][y + 1] == '.') {
stack.push(new Point(x,y+1));
continue;
}
}
stack.pop(); /*if the stack is empty and we didn't yet reach to the end ,
this mean that there is no path */
if(stack.isEmpty()){
System.out.println("there is no path");
System.exit(0);
}
}
int [][]dfs = new int[stack.size()][2];
for (int i = stack.size()-1; i >=0; i--) {
dfs[i][0]=((Point)stack.peek()).x;
dfs[i][1]=((Point)stack.pop()).y;
}
return dfs;
}
public void print(int [][]arr){
for (int i = 0; i < arr.length; i++) {
System.out.printf(Locale.ENGLISH,"{%d, %d}",arr[i][0],arr[i][1]);
if(i< arr.length-1)
System.out.print(", ");
}
}
public static void main(String[] args) throws FileNotFoundException {
File maze = new File("C:\\Users\\Administrator.ENO-20171214VED\\Desktop\\Maze Solver.txt");
Scanner scan=new Scanner(System.in);
// try {
MazeSolver m = new MazeSolver();
int[][] dfs;
int[][] bfs;
bfs = m.solveBFS(maze);
if(bfs[0][0]==-1 && bfs[1][0]==-1){
System.out.println("there is no path");
}
else {
System.out.print("BFS: ");
m.print(bfs);
}
dfs = m.solveDFS(maze);
System.out.print("\nDFS: ");
m.print(dfs);
// }
//catch (Exception e){
// System.out.println( "Error : "+e.getMessage());
//}
}
}