reorder list

Author: se6816

reorder-list/se6816.java

@@ -0,0 +1,25 @@
+
+class Solution {
+    public void reorderList(ListNode head) {
+        if(head.next == null) return;
+
+        ListNode prev = null;
+        while (true) {
+            ListNode tail = head;
+            while (tail.next != null) {
+                prev = tail;
+                tail = tail.next;
+            }
+            
+            if (prev == head) break;  
+            
+            // tail 이동
+            ListNode headNext = head.next;
+            prev.next = null;
+            head.next = tail;
+            tail.next = headNext;
+            
+            head = headNext;
+        }
+    }
+}