Leetcode:Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.
給你2個排序好的單鏈表，返回一個merge的單鏈表。
鏈表數據結構：

  public class ListNode {
      int val;
      ListNode next;
      ListNode(int x) {
          val = x;
          next = null;
      }
  }

2個單鏈表各設一個遊標，並設一個result節點。
對比2個遊標，並將result指向較小的那個遊標，較小的遊標再向後移一位。

    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode cur1 = l1;
        ListNode cur2 = l2;
        ListNode head, result, temp1, temp2;
        if (l1 == null && l2 == null)
            return null;
        if (l1 == null)
            return l2;
        if (l2 == null)
            return l1;
        head = cur1.val < cur2.val ? cur1 : cur2;
        result = new ListNode(0);
        while (cur1 != null & cur2 != null) {
            result.next = cur1.val < cur2.val ? cur1 : cur2;
            result=result.next;
            if (cur1.val < cur2.val) {
                cur1 = cur1.next;
            } else 
                cur2 = cur2.next;
        }
        if (cur1 == null)
            result.next = cur2;

        if (cur2 == null)
            result.next = cur1;
        return head;
    }