search catch up

src/Search.java

@@ -1,4 +1,11 @@
-public class Search {
+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.
      * Returns a 2-element int array: [row, col] of the closest 'c'. If there are multiple
@@ -27,8 +34,127 @@ public class Search {
      * @throws EscapedRatException if there is no rat in the maze
      * @throws CrowdedMazeException if there is more than one rat in the maze
      * @throws HungryRatException if there is no reachable cheese
+     * 
+     * bfs when they asking for shortest route or least amount / length
+     * dfs is how many / count 
+     * 
      */
-    public static int[] nearestCheese(char[][] maze) throws EscapedRatException, CrowdedMazeException, HungryRatException {
-        return null;
+
+
+    public static int[] nearestCheese(char[][] maze) throws EscapedRatException, CrowdedMazeException, HungryRatException 
+    {
+        //find your starting point
+        int [] start = findRat(maze);
+
+        boolean [][] visited = new boolean[maze.length][maze[0].length];
+        Queue<int[]> queue = new LinkedList<>();
+
+        //put start in the queue
+        //initialy queue will now have start
+        queue.add(start);
+
+        //means it will contain something 
+        while(!queue.isEmpty())
+        {
+            //poll is pop in queue
+            //this will now take start and put it into current 
+            int[] current = queue.poll();
+            int row = current[0];
+            int col = current[1];
+
+            if(visited[row][col])
+            {
+                continue;
+            }
+            visited[row][col] = true;
+
+            //if we found cheese
+            if(maze[row][col] == 'c')
+            {
+                //return location of c
+                return current;
+            }
+
+            //adding possible moves each location we go.
+            queue.addAll(possibleMoves(current, maze));
+
+        }
+
+        throw new HungryRatException();
+
+    }
+
+    public static List<int[]> possibleMoves(int[]current, char[][]maze)
+    {
+        //taking the int out of the array 
+        int row = current[0];
+        int col = current[1];
+
+        //up, down, left, right
+        int[][] directions = {{-1,0}, {1,0}, {0,-1}, {0,1}};
+
+        List<int[]> neighbors = new ArrayList<>();
+
+        //each row in our 2d matrix
+        for (int[] direction : directions)
+        {
+            //create a new varaible
+            //moves
+            int changeR = direction[0];
+            int changeC = direction[1];
+            int newR = changeR + row;
+            int newC = changeC + col;
+
+            if (newR >= 0 && newR < maze.length && newC >= 0 && newC < maze[newR].length && maze[newR][newC] != 'w')
+            {
+                int[] validLocation = new int[] {newR, newC};
+                neighbors.add(validLocation);
+            }
+        }
+        return neighbors;
+
+    }
+
+
+
+
+    //this method helps establish where explorer starts
+    //start method
+    public static int[] findRat(char[][] maze) throws EscapedRatException, CrowdedMazeException
+    {
+
+        int[] ratLocation = null;
+
+        for (int row = 0; row < maze.length; row++)
+        {
+            for(int col = 0; col < maze[0].length; col++)
+            {
+                //check to see if R is in the maze
+                if(maze[row][col] == 'R')
+                {
+                    //check to see if theres more than one R
+                    if(ratLocation != null)
+                    {
+                        throw new CrowdedMazeException();
+                    }
+                    ratLocation = new int[] {row, col};
+                    // ratLocation[0] == row;
+                    // ratLocation[1] == col;
+                }
+
+            }
+        }
+        //if ratlocaton is null we cant find it
+        if (ratLocation == null)
+        {
+            throw new EscapedRatException();
+        }
+
+        return ratLocation;
+
+
     }
+
+
+
 }