feat: add states

app/src/main/java/sudoku/solver/Solver.java

@@ -68,10 +68,9 @@ public class Solver {
      * @param oldDoku MultiDoku, MultiDoku dont on veut le nombre de solutions.
      * @return int, nombre de solutions possibles.
      */
-    public static int countSolution(MultiDoku oldDoku) {
+    public static int countSolution(MultiDoku doku) {
         int result = 0;
 
-        MultiDoku doku = oldDoku.clone();
 
         if (doku.isSolved()) {
             return 1;
@@ -83,11 +82,12 @@ public class Solver {
         List<Integer> possibleSymbols = cellToFill.getPossibleSymbols();
 
         for (int symbol : possibleSymbols) {
+            doku.getStateManager().pushState();
             cellToFill.setSymbolIndex(symbol);
-            if (Solver.solve(doku) != null) {
+            if (Solver.solve(doku)) {
                 result++;
             }
-            cellToFill.setSymbolIndex(Cell.NOSYMBOL);
+            doku.getStateManager().popState();
         }
 
         return result;
@@ -98,37 +98,35 @@ public class Solver {
      * @param doku MultiDoku, MultiDoku à résoudre.
      * @return boolean, valant true si le MultiDoku est résolu, false sinon.
      */
-    public static MultiDoku solve(MultiDoku oldDoku) {
+    public static boolean solve(MultiDoku doku) {
         if (Thread.interrupted())
             throw new CancellationException("User wants to stop the solver");
 
-        MultiDoku doku = oldDoku.clone();
-
         if (doku.isSolved()) {
-            return doku;
+            return true;
         }
 
         Cell cellToFill = doku.getFirstEmptyCell();
         if (cellToFill == null) {
-            return null;
+            return false;
         }
 
         List<Integer> possibleSymbols = cellToFill.getPossibleSymbols();
         if (possibleSymbols.isEmpty()) {
-            return null;
+            return false;
         }
 
         for (int symbol : possibleSymbols) {
 
             cellToFill.setSymbolIndex(symbol);
-            if (Solver.solve(doku) != null) {
+            if (Solver.solve(doku)) {
-                return doku;
+                return true;
             } else {
                 cellToFill.setSymbolIndex(Cell.NOSYMBOL);
             }
 
         }
-        return null;
+        return false;
     }
 
     /**

app/src/main/java/sudoku/structure/MultiDoku.java

@@ -19,13 +19,11 @@ public class MultiDoku {
 	 */
 	private final List<Sudoku> subGrids;
 
+	private final StateManager stateManager;
+
 	public MultiDoku(List<Sudoku> subGrids) {
 		this.subGrids = subGrids;
-	}
+		this.stateManager = new StateManager(this);
-
-	public MultiDoku clone() {
-		// TODO: ahhhhhhhhhhhhhhhhhhhhhhh
-		return SudokuSerializer.deserializeSudoku(SudokuSerializer.serializeSudoku(this));
 	}
 
 	/**
@@ -167,4 +165,9 @@ public class MultiDoku {
 			filledCell.setImmutable();
 		}
 	}
+
+	public StateManager getStateManager() {
+		return stateManager;
+	}
+
 }

app/src/main/java/sudoku/structure/StateManager.java

@@ -0,0 +1,41 @@
+package sudoku.structure;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Stack;
+
+//TODO: doc
+public class StateManager {
+
+	private final Stack<Map<Cell, Integer>> states;
+	private final MultiDoku doku;
+
+	public StateManager(MultiDoku doku) {
+		this.states = new Stack<>();
+		this.doku = doku;
+	}
+
+	public void pushState() {
+		states.add(new HashMap<>());
+		saveState();
+	}
+
+	public void popState() {
+		assert (states.size() > 0);
+		restoreState();
+		states.pop();
+	}
+
+	private void restoreState() {
+		for (var entry : this.states.getLast().entrySet()) {
+			entry.getKey().setSymbolIndex(entry.getValue());
+		}
+	}
+
+	private void saveState() {
+		for (Cell cell : this.doku.getCells()) {
+			states.getLast().put(cell, cell.getSymbolIndex());
+		}
+	}
+
+}