Insertion Sort List

/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     ListNode *next;
*     ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *insertionSortList(ListNode *head) {
if(!head||!head->next) return head;
ListNode dummy(-1);
dummy.next=head;
ListNode *p=dummy.next,*q=head->next;
p->next=NULL;
while(q){
ListNode* prev=&dummy,*cur=prev->next;
while(prev){//寻找插入位置
if(!cur||q->val<=cur->val){
prev->next=q;
q=q->next;
prev->next->next=cur;
break;
}
else{
prev=cur;
cur=cur->next;
}
}
}
return dummy.next;
}
};