leetCode(4):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==NULL)
    return NULL;
    ListNode* p=head;
    ListNode* start=p->next;
    while(start)
    {
    ListNode* q=p;
    while(q!=start && q->val < start->val)
    {
    q=q->next;
    }
    if(q!=start)
    {
    ListNode* tmpNode=q;
    int tmp=start->val;
    while(tmpNode!=start)
    {
    int tmp1=tmpNode->val;
    tmpNode->val=tmp;
    tmp=tmp1;
    tmpNode=tmpNode->next;
    }
    start->val=tmp;
    }
    start=start->next;
    }
    return head;

    }
};