1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
|
package com.company;
class Coordinates{
public int x,y; //for storing coordinates as object
Coordinates(int x,int y){
this.x=x;
this.y=y;
}
}
public class BFS { //BFS main class
static Coordinates[] queue=new Coordinates[1000]; //queue of coordinates
private static int front=-1;
private static int rear=-1;
static void enqueue(Coordinates coord){ //enqueue function
if(front==-1 && rear==-1){
front=0;
rear=0;
}
else{
rear++;
}
queue[rear]= coord;
}
static void dequeue(){ //dequeue operation
if(front==0 && rear==0){
front=-1;
rear=-1;
}
else{
front++;
}
}
private static final int[][] dir=new int[][]{ //traversing directions
{0,1}, //right
{1,0}, //down
{0,-1}, //left
{-1,0} //up
};
static void bfs(char[][] maze,Coordinates start,boolean[][] visited){
int curx;
int cury;
for(int i=0;i<4;i++){
curx=start.x;
cury=start.y;
curx+=dir[i][0];
cury+=dir[i][1];
if(curx<0 || cury<0 || curx> maze.length-1 || cury>maze.length-1){
continue; //for square... out of maze check
}
else if(maze[curx][cury]=='$'){
System.out.println("Path found");
System.exit(0);
}
else if(visited[curx][cury] || maze[curx][cury]=='#'){
continue;
}
else if(maze[curx][cury]=='_'){
enqueue(new Coordinates(curx,cury));
visited[curx][cury]=true;
}
}
dequeue();
if(front==-1){
System.out.println("path not found");
System.exit(0);
}
else
bfs(maze,queue[front],visited);
}
public static void main(String[] args) {
char[][] maze = {{'*','#','#'},
{'_','_','#'},
{'_','#','$'},
};
Coordinates start=new Coordinates(0,0);
boolean[][] visited=new boolean[maze.length][maze.length];
for(int i=0;i< maze.length;i++){
for(int j=0;j<maze.length;j++) {
visited[i][j]=false;
}
}
visited[0][0]=true;
enqueue(start);
bfs(maze,start,visited);
}
}
|