Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.
两个有序单链表合并。
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *mergeTwoLists(ListNode *l1, ListNode *l2) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
if (l1 == NULL && l2 == NULL)
return NULL;
ListNode* newHead = new ListNode(0);
ListNode* newCurrent = newHead;
ListNode* next1 = l1;
ListNode* next2 = l2;
while(l1 != NULL && l2 != NULL)
{
if (l1->val < l2->val)
{
next1 = l1->next;
newCurrent->next = l1;
l1->next = NULL;
l1 = next1;
}
else
{
next2 = l2->next;
newCurrent->next = l2;
l2->next = NULL;
l2 = next2;
}
newCurrent = newCurrent->next;
}
if(l1 != NULL)
newCurrent->next = l1;
else
newCurrent->next = l2;
newCurrent = newHead;
newHead = newHead->next;
delete newCurrent;
return newHead;
}
};