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。
class Solution {
public:
ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
{
if(pHead1==NULL)
return pHead2;
if(pHead2==NULL)
return pHead1;
ListNode* dummy = new ListNode(-1);
ListNode* p = dummy; //与dummy->next = p的思路不同
while(pHead1!=NULL&&pHead2!=NULL)
{
if(pHead1->val<pHead2->val)
{
p->next = pHead1;
pHead1 = pHead1->next;
p = p->next;
}
else
{
p->next = pHead2;
pHead2 = pHead2->next;
p = p->next;
}
}
if(pHead1==NULL)
p->next = pHead2;
else if(pHead2==NULL)
p->next = pHead1;
return dummy->next;
}
};
