merge

app/src/main/java/sudoku/MutableCell.java

@@ -17,17 +17,27 @@ public class MutableCell extends Cell{
 		this.possibleSymbols = new ArrayList<>();
 	}
 
+	public MutableCell(MutableCell currentCell) {
+		super(currentCell);
+		this.possibleSymbols = currentCell.getPossibleSymbols();
+	}
+
 	public void setSymbolIndex(int symbolIndex) {
 		this.symbolIndex = symbolIndex;
 	}
 
+	public void setPossibleSymbols(List<Integer> possibleSymbols) {
+		this.possibleSymbols.clear();
+		this.possibleSymbols.addAll(possibleSymbols);
+	}
+
 	/**
 	 * Remove the current symbolIndex and returns it
 	 * @return integer symbolIndex cleared
 	 */
 	public int clearCurrentSymbol() {
 		int i = this.symbolIndex;
-		setSymbolIndex(NOSYMBOLE);
+		setSymbolIndex(NOSYMBOL);
 		return i;
 	}