[Leetcode][021] Merge Two Sorted Lists (Java)

题目在这里: https://leetcode.com/problems/merge-two-sorted-lists/

【标签】Linked List

【题目分析】这个题目就是merge sort在 Linked List中的变形。不多说，直接上代码了

　　public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode dummyHead = new ListNode(-1);
        ListNode node = dummyHead;
        while (l1 != null && l2 != null) {
            if (l1.val <= l2.val) {
                node.next = l1;
                l1 = l1.next;
            } else {
                node.next = l2;
                l2 = l2.next;
            }
            node = node.next;
        }
        // append the remaining list
        node.next = (l1 != null) ? l1 : l2;
        return dummyHead.next;
17　　}