diff --git a/src/main/java/grafos/CFG.java b/src/main/java/grafos/CFG.java
index 24dc65c..3b301c3 100644
--- a/src/main/java/grafos/CFG.java
+++ b/src/main/java/grafos/CFG.java
@@ -7,7 +7,7 @@ import java.util.*;
 
 public class CFG {
 	private final List<Node> nodes = new ArrayList<Node>();
-	private final Map<Node, List<Node>> edges = new HashMap<Node, List<Node>>();
+	private final List<Map.Entry<Node, Node>> edges = new LinkedList<>();
 	private Node beginNode, endNode;
 
 	public void addNode(Node stmt) {
@@ -20,13 +20,7 @@ public class CFG {
 	}
 
 	public void connect(Node begin, Node end) {
-		if (edges.containsKey(begin) && !edges.get(begin).contains(end)) {
-			edges.get(begin).add(end);
-		} else {
-			List<Node> dest = new ArrayList<Node>();
-			dest.add(end);
-			edges.put(begin, dest);
-		}
+		edges.add(new HashMap.SimpleEntry<>(begin, end));
 	}
 
 	public void connect(Collection<Node> begin, Node end) {
@@ -52,10 +46,8 @@ public class CFG {
 
 	public List<String> toStringList() {
 		List<String> res = new LinkedList<String>();
-		for (Map.Entry<Node, List<Node>> e : edges.entrySet()) {
-			for (Node dest : e.getValue()) {
-				res.add(edge2str(e.getKey(), dest));
-			}
+		for (Map.Entry<Node, Node> e : edges) {
+			res.add(edge2str(e.getKey(), e.getValue()));
 		}
 		return res;
 	}
@@ -69,7 +61,16 @@ public class CFG {
 			return "Start";
 		if (s == endNode)
 			return "Stop";
-		int index = nodes.indexOf(s);
-		return "\"(" + index + ") " + s.toString().replace("\"", "\\\"") + "\"";
+		int index = -1;
+		for (int i = 0; i < nodes.size(); i++) {
+			if (nodes.get(i) == s) {
+				index = i;
+				break;
+			}
+		}
+		if (index == -1)
+			throw new RuntimeException("Internal error, can't find node");
+		return "\"(" + index + ", " + s.getRange().get().begin.line + ") "
+				+ s.toString().replace("\"", "\\\"") + "\"";
 	}
 }