147. 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 = new ListNode(-1);
        
        while(head){
            ListNode *pNext = head->next;
            ListNode *pCur = dummy;
            while(pCur->next&&pCur->next->val<head->val){
                pCur = pCur->next;
            }
            head->next = pCur->next;
            pCur->next = head;
            head = pNext;
        }
        return dummy->next;
    }
};