Sort vertex lists by vertex label before making adjacency matrix

src/main/java/Vertex.java

@@ -1,6 +1,6 @@
 import java.io.Serializable;
 
-public class Vertex implements Serializable {
+public class Vertex implements Serializable, Comparable<Vertex> {
     private  SequenceType type;
     private  Integer vertexLabel;
     private  Integer sequence;
@@ -89,4 +89,9 @@ public class Vertex implements Serializable {
         return sb.toString();
     }
 
+    @Override
+    public int compareTo(Vertex other) {
+        return this.vertexLabel - other.getVertexLabel();
+    }
+
 }