fix LinkedList utils

fishercoder1534 · fishercoder1534 · commit 2c80c2d5e2b5 · 2018-12-20T20:05:39.000-08:00
diff --git a/src/main/java/com/fishercoder/common/classes/ListNode.java b/src/main/java/com/fishercoder/common/classes/ListNode.java
@@ -52,28 +52,22 @@ public static ListNode createSinglyLinkedList() {
         return head;
     }
 
-    /**
-     * TODO: this function is NOT working as supposed to, I need to fix it! Commit from my Windows machine!
-     */
     public static ListNode createSinglyLinkedList(List<Integer> listValues) {
         if (listValues == null || listValues.size() == 0) {
             throw new IllegalArgumentException(
                     "Please pass in a valid listValues to create a singly linked list.");
         }
         ListNode head = new ListNode(listValues.get(0));
-        for (int i : listValues) {
-            appendNode(head, i);
+        ListNode tmp = head;
+        for (int i = 1; i < listValues.size(); i++) {
+            ListNode next = new ListNode(listValues.get(i));
+            tmp.next = next;
+            tmp = tmp.next;
         }
         printList(head);
         return head;
     }
 
-    private static void appendNode(ListNode head, int i) {
-        ListNode node = new ListNode(i);
-        head.next = node;
-//        head = head.next;
-    }
-
     public static void printList(ListNode head) {
         ListNode temp = head;
         System.out.println();
