merge two sorted lists

Author: se6816

merge-two-sorted-lists/se6816.java

@@ -0,0 +1,51 @@
+/**
+    연결 리스트를 활용하여, 하나의 리스트를 만드는 방식
+    시간 복잡도 : O(N+M)
+    공간 복잡도 : O(1)
+ */
+class Solution {
+    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
+        NodeList list=new NodeList();
+        ListNode temp = null;
+        while(list1 != null && list2 != null){
+            if(list1.val >= list2.val){
+                list2 = merge(list, list2);
+            }else{
+                list1 = merge(list, list1);
+            }
+        }
+        while(list1 !=null){
+            list1 = merge(list, list1);
+        }
+        while(list2 != null){
+            list2 = merge(list, list2);
+        }
+        return list.head;
+    }
+    public class NodeList {
+        ListNode head = null;
+        ListNode tail = null;
+        public NodeList(){
+        }
+
+        public void add(ListNode tempNode){
+            if(head == null){
+                head = tempNode;
+                tail = head;
+            }else{
+                tail.next = tempNode;
+                tail = tail.next;
+            }
+        }
+
+    }
+
+    public ListNode merge(NodeList list, ListNode target) {
+        ListNode tempNode = null;
+        tempNode = target;
+        list.add(target);
+        target = target.next;
+        tempNode.next = null;
+        return target;
+    }
+}