C++/代码:

class Solution {
public:
    ListNode* Merge(ListNode* pHead1, ListNode* pHead2) {
        auto dummy = new ListNode(-1); //定义一个虚拟表头
        auto cur = dummy; //定义一个移动节点
        while (pHead1 && pHead2) { //遍历
            if (pHead1->val < pHead2->val) { //小的数放前面
                cur->next = pHead1; //1->3
                pHead1 = pHead1->next;
            }
            else {
                cur->next = pHead2; //1->3
                pHead2 = pHead2->next;
            }
            cur = cur->next;
        }
        if (pHead1) cur->next = pHead1; //因为最后总会多一个数,无法进行比较的
        else cur->next = pHead2; //所以那个链表多了就放那个链表中的数到最后
        return dummy->next;
    }
};