题目描述

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(NULL) {
    }
};*/
class Solution {
public:
    ListNode* Merge(ListNode* pHead1, ListNode* pHead2) {
        ListNode* head = new ListNode(0);
        ListNode* ptr = head;
        while(pHead1 != nullptr && pHead2 != nullptr) {
            if(pHead1->val < pHead2->val) {
                ptr->next = pHead1;
                pHead1 = pHead1->next;
            }
            else {
                ptr->next = pHead2;
                pHead2 = pHead2->next;
            }
            ptr = ptr->next;
        }
        if(pHead1 != nullptr)
            ptr->next = pHead1;
        if(pHead2 != nullptr)
            ptr->next = pHead2;
        return head->next;
    }
};