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:
//类似归并,注意指针操作的细节就好
ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
{
if (pHead1 == nullptr)
return pHead2;
if (pHead2 == nullptr)
return pHead1;
ListNode* p = nullptr, *pHead = nullptr;
if(pHead1->val < pHead2->val)
{
pHead = p = pHead1;
pHead1 = pHead1->next;
}
else
{
pHead = p = pHead2;
pHead2 = pHead2->next;
}
while (pHead1 != nullptr && pHead2 != nullptr)
{
if(pHead1->val < pHead2->val)
{
p->next = pHead1;
p = p->next;
pHead1 = pHead1->next;
}
else
{
p->next = pHead2;
p = p->next;
pHead2 = pHead2->next;
}
}
if(pHead1 != nullptr)
p->next = pHead1;
if(pHead2 != nullptr)
p->next = pHead2;
return pHead;
}
};