2、合并2个有序链表

合并链表

代码实现

class ListNode1 {
    int val;
    ListNode1 next;
    public ListNode1(int value) {
        this.val = value;
    }
}

public class Solution {

    public ListNode1 mergeTwoList(ListNode1 l1, ListNode1 l2) {
        ListNode1 preHead = new ListNode1(-1);
        ListNode1 cur = preHead;
        while (l1 != null && l2 != null) {
            if (l1.val < l2.val) {
                cur.next = l1;
                l1 = l1.next;
            } else {
                cur.next = l2;
                l2 = l2.next;
            }
            cur = cur.next;
        }

        cur.next = l1 == null ? l2 : l1;

        return preHead.next;
    }
}