Implemented BFS. Seems to be fully functioning. Need to fix generation of boards to prevent off chance of solved generations.

src/Assignments/A1/Driver.java

@@ -4,6 +4,7 @@ package Assignments.A1;
 
 import Assignments.A1.models.Board;
 import Assignments.A1.models.BoardGenerator;
+import Assignments.A1.solving_algorithms.BFS;
 import Assignments.A1.solving_algorithms.DFS;
 
 import java.util.ArrayList;
@@ -28,12 +29,12 @@ public class Driver {
         int successes = 0;
         for (int run = 0; run < 100; run++) {
             Board board = BoardGenerator.generateBoard();
-            DFS solver = new DFS();
+//            DFS solver = new DFS();
+            BFS solver = new BFS();
             Date start = new Date();
-            Board result = solver.dfs(board,0);
+            Board result = solver.traverse(board);
             Date end = new Date();
             if (result != null) {
-                System.out.println("solved");
                 long runtime = end.getTime() - start.getTime();
                 timer.add(runtime);
                 successes++;

src/Assignments/A1/resources/Parameters.java

@@ -11,4 +11,4 @@ public class Parameters {
     /* Used to prevent DFS from going down only 1 branch */
     public static final int MAX_DEPTH = 100; // Max number of moves in 8-Puzzle's are 31 moves if solvable.
 
-}
+}

src/Assignments/A1/solving_algorithms/BFS.java

@@ -1,7 +1,94 @@
 package Assignments.A1.solving_algorithms;
 
+import Assignments.A1.models.Board;
+import Assignments.A1.models.Move;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.PriorityQueue;
+
 public class BFS {
 
+    private final Board solved = new Board();
+    private final HashSet<Board> visited = new HashSet<>();
 
-    /* Checking out new Branch for BFS Development to prevent harm to DFS existing algorithm. */
+    public Board traverse(Board root) {
+        PriorityQueue<BoardNode> boards = new PriorityQueue<>();
+        boards.add(new BoardNode(root));
+        BoardNode node = null;
+        while (!boards.isEmpty()) {
+            node = boards.poll();
+            if (visited.contains(node.board)) {
+                continue;
+            }
+            visited.add(node.board);
+            List<Move> children = node.board.getMoves();
+            for (Move move : children) {
+                Board child = new Board(node.board);
+                child.swap(move);
+                boards.add(new BoardNode(child));
+            }
+        }
+        return node.board;
+    }
+}
+
+class BoardNode implements Comparable<BoardNode> {
+
+    public int heuristic;
+    public Board board;
+
+    public BoardNode(Board board) {
+        this.heuristic = this.getCost(board);
+        this.board = board;
+    }
+
+    private int getCost(Board board) {
+        int cost = 0;
+        for (int i = 0; i < 9; i++) {
+            int currValue = board.getPiece(i);
+            cost += Math.abs(i - this.idealIndex(i));
+        }
+        return cost;
+    }
+
+    private int idealIndex(int value) {
+        int result = -1;
+        switch(value) {
+            case 0:
+                result =  4;
+                break;
+            case 1:
+                result =  0;
+                break;
+            case 2:
+                result =  1;
+                break;
+            case 3:
+                result =  2;
+                break;
+            case 4:
+                result =  5;
+                break;
+            case 5:
+                result =  8;
+                break;
+            case 6:
+                result =  7;
+                break;
+            case 7:
+                result =  6;
+                break;
+            case 8:
+                result =  3;
+                break;
+
+        }
+        return result;
+    }
+
+    @Override
+    public int compareTo(BoardNode o) {
+        return Integer.compare(this.heuristic, o.heuristic);
+    }
 }