147. Insertion Sort List

class Solution {
public:
    ListNode* insertionSortList(ListNode* head) {
        if(!head)return head;
        queue<ListNode*>q;
        ListNode* p=head;
        while(p){
            q.push(p);
            p=p->next;
        }
        head=NULL;
        while(!q.empty()){
            p=head;
            ListNode *past_p=NULL;
            ListNode* t=q.front();
            q.pop();
            while(p&&p->val<t->val){
                past_p=p;
                p=p->next;
            }
            t->next=p;
            if(past_p==NULL)
                head=t;
            else past_p->next=t;
        }
        return head;   
    }
};