add josephu question

src/main/java/io/github/ehlxr/datastructure/linkedlist/DoubleLinkedListDemo.java

@@ -53,6 +53,9 @@ public class DoubleLinkedListDemo {
     }
 }
 
+/**
+ * 双向链表
+ */
 class DoubleLinkedList {
     private final HeroNode2 head = new HeroNode2(0, "", "");
 

src/main/java/io/github/ehlxr/datastructure/linkedlist/Josephu.java

@@ -38,6 +38,9 @@ public class Josephu {
     }
 }
 
+/**
+ * 循环单向链表
+ */
 class CircleSingleLinkedList {
     private Boy first = null;