lintcode-链表插入排序

1->3->2->0->null

0->1->2->3->null

/**
* Definition of ListNode
* class ListNode {
* public:
*     int val;
*     ListNode *next;
*     ListNode(int val) {
*         this->val = val;
*         this->next = NULL;
*     }
* }
*/
class Solution {
public:

ListNode *insertionSortList(ListNode *head) {
if(!head)
return nullptr;
ListNode *dummy=new ListNode(0);
ListNode *temp=nullptr;

        while(head){     //head节点插入dummy链表中
temp=dummy;  //temp指向dummy的头节点
ListNode *next=head->next;
while(temp->next!=nullptr&&temp->next->val<head->val) //寻找插入点
temp=temp->next;
head->next=temp->next;  
temp->next=head;
head=next;
}
temp=dummy;
dummy=dummy->next;
free(temp);
return dummy;
}
};