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/
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode next;
* ListNode(int x) : val(x), next(NULL) {}
* };
/

class Solution {
public:
ListNode merge(ListNode l1, ListNode l2) {
// 创建一个虚拟头节点，简化链表操作
ListNode dummy = new ListNode(0);
ListNode* curr = dummy;

    while (l1 && l2) {
        if (l1->val <= l2->val) {
            curr->next = l1;
            l1 = l1->next;
        } else {
            curr->next = l2;
            l2 = l2->next;
        }
        curr = curr->next;
    }

    // 将剩余链表部分连接到合并链表的末尾
    if (l1)
        curr->next = l1;
    else if (l2)
        curr->next = l2;

    // 返回合并后的链表头节点
    ListNode* mergedList = dummy->next;
    delete dummy;
    return mergedList;
}

};
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