completed

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.
@@ -29,6 +34,78 @@ public class Search {
      * @throws HungryRatException if there is no reachable cheese
      */
     public static int[] nearestCheese(char[][] maze) throws EscapedRatException, CrowdedMazeException, HungryRatException {
-        return null;
+            int[] start = findRat(maze);
+
+        Queue<int[]> queue = new LinkedList<>();
+
+        queue.add(start);
+
+        boolean[][] visited = new boolean[maze.length][maze[0].length];
+
+        while(!queue.isEmpty()) {
+            int[] current = queue.poll();
+            int curR = current[0];
+            int curC = current[1];
+
+            if(maze[curR][curC] == 'c') {
+                return current;
+            }
+            if(visited[curR][curC]) {
+                continue;
+            }
+
+            visited[curR][curC] = true;
+
+            List<int[]> nextMoves = possibleMoves(maze, current);
+            queue.addAll(nextMoves);
+        }
+
+        throw new HungryRatException();
     }
+
+    public static List<int[]> possibleMoves(char[][]maze, int[] currentLoc) {
+        List<int[]> moves = new ArrayList<>();
+        int[][] steps = {
+            {1, 0},
+            {-1, 0},
+            {0, 1},
+            {0, -1}
+        };
+
+        int curR = currentLoc[0];
+        int curC = currentLoc[1];
+
+        for(int[] step : steps) {
+            int newR = curR + step[0];
+            int newC = curC + step[1];
+
+            if(newR >= 0 && newR < maze.length &&
+               newC >= 0 && newC < maze[0].length &&
+               maze[newR][newC] != 'w') {
+                moves.add(new int[]{newR, newC});
+               }
+        }
+
+        return moves;
+    }
+
+    public static int[] findRat(char[][] maze) throws CrowdedMazeException, EscapedRatException {
+        int ratCount = 0;
+        int[] ratLocation = null;
+
+        for(int r = 0; r < maze.length; r++) {
+            for(int c = 0; c < maze[0].length; c++) {
+                if(maze[r][c] == 'R') {
+                    ratLocation = new int[]{r, c};
+                    ratCount++;
+                }
+            }
+        }
+
+        if(ratCount > 1) throw new CrowdedMazeException();
+        if(ratCount == 0) throw new EscapedRatException();
+
+        return ratLocation;
+    }
+
 }