16.Merge_Two_Sorted_List

// 输入两个单调递增的链表，输出两个链表合成后的链表，当然我们需要合成后的链表满足单调不减规则。

struct ListNode {
    int val;
    struct ListNode* next;
    ListNode(int x) : val(x), next(nullptr) {}
};

class Solution {
public:
    ListNode* Merge(ListNode* pHead1, ListNode* pHead2) {
        auto fakeHead = new ListNode(0), cur = fakeHead;
        while (pHead1 && pHead2) {
            if (pHead1->val < pHead2->val) {
                cur->next = pHead1;
                pHead1 = pHead1->next;
            } else {
                cur->next = pHead2;
                pHead2 = pHead2->next;
            }
            cur = cur->next;
        }
        cur->next = pHead1 ? pHead1 : pHead2;
        return fakeHead->next;
    }
};