saving

src/Search.java

@@ -1,3 +1,8 @@
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
 public class Search {
      /**
      * Finds the location of the nearest reachable cheese from the rat's position.
@@ -28,7 +33,115 @@ public class Search {
      * @throws CrowdedMazeException if there is more than one rat in the maze
      * @throws HungryRatException if there is no reachable cheese
      */
-    public static int[] nearestCheese(char[][] maze) throws EscapedRatException, CrowdedMazeException, HungryRatException {
-        return null;
+    public static int[] nearestCheese(char[][] maze) throws EscapedRatException, CrowdedMazeException, HungryRatException 
+    {
+        boolean[][] visited = new boolean[maze.length][maze[0].length];
+        int[] start = locateRat(maze);
+
+        //Queue
+        Queue<int[]> queue = new LinkedList<>();
+
+        //add
+        queue.add(start);
+
+        //loop
+        while(!queue.isEmpty())
+        {
+            int[] current = queue.poll();
+            int curR = current[0];
+            int curC = current[1];
+
+            if(visited[curR][curC])
+            {
+                continue;
+            }
+            visited[curR][curC] = true;
+
+            if(maze[curR][curC] == 'c')
+            {
+                return current;
+            }
+
+            queue.addAll(getNeighbors(maze, current));
+        }
+
+        throw new HungryRatException();
+
+        /*
+            empty q
+            q.add(start)
+            while q is not empty
+                current = q.pop
+                if visited: continue
+                    mark visited
+                if current is cheese: return current
+                    q.add(neighbors) add all neighbors to q
+
+            hungryRatException
+        */ 
+
+    }
+
+
+
+    public static List<int[]> getNeighbors(char[][] maze, int[] current)
+    {
+        int curR = current[0];
+        int curC = current[1];
+
+        int[][] directions = {
+            {-1, 0}, //up
+            {1, 0}, //down
+            {0, -1}, //left
+            {0, 1}, //right
+        };
+
+        List<int[]> possibleMoves = new ArrayList<>();
+
+        for(int[] direction : directions)
+        {
+            int changeR = direction[0];
+            int changeC = direction[1];
+
+            int newR = curR + changeR;
+            int newC = curC + changeC;
+
+            if(newR >= 0 && newR < maze.length && newC >= 0 && newC < maze[newR].length && maze[newR][newC] != 'w')
+            {
+                int[] validMove = new int[]{newR,newC};
+                possibleMoves.add(validMove);
+            }
+        }
+
+        return possibleMoves;
+    }
+
+    public static int[] locateRat(char[][] maze) throws EscapedRatException, CrowdedMazeException
+    {   
+        int[] location = null;
+
+        //Searching
+        for(int r = 0; r < maze.length; r++)
+        {
+            for(int c = 0; c < maze[r].length; c++)
+            {
+                if(maze[r][c] == 'R')
+                {
+                    if(location != null)
+                    {
+                        throw new CrowdedMazeException();
+                    }
+                    location = new int[]{r,c};
+                } 
+            }
+        }
+
+
+        if(location == null)
+        {
+            //Didnt Find
+            throw new EscapedRatException();
+        }
+        return location;
     }
 }