剑指offer【c++】合并两个排序的链表
题目: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。
思路:比较简单,依次迭代
代码:
/*
struct ListNode {
int val;
struct ListNode *next;
ListNode(int x) :
val(x), next(NULL) {
}
};*/
class Solution {
public:
ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
{
if (pHead1 == NULL)
return pHead2;
if (pHead2 == NULL)
return pHead1;
ListNode* pHead = NULL;
ListNode* res = NULL;
while(pHead1 != NULL && pHead2 != NULL)
{
if (pHead1->val < pHead2->val)
{
if (res == NULL)
{
pHead = pHead1;
res = pHead1;
}
else
{
res->next = pHead1;
res = res->next;
}
pHead1 = pHead1->next;
}
else
{
if(res == NULL)
{
pHead = pHead2;
res = pHead2;
}
else
{
res->next = pHead2;
res = res->next;
}
pHead2 = pHead2->next;
}
}
if (pHead1 == NULL)
res->next = pHead2;
if (pHead2 == NULL)
res->next = pHead1;
return pHead;
}
};