ListNode* sortLinkList(ListNode *head) {
if (head == NULL) return NULL;
if (head->next == NULL) return head;
ListNode* head2 = partitionLinkList(head);
head = sortLinkList(head);
head2 = sortLinkList(head2);
return mergeLinkList(head, head2);
}
ListNode* sortList(ListNode* head) {
if(!head || !head->next) return head;
ListNode *slow = head, *fast = head->next;
while(fast && fast->next)
{
slow = slow->next;
fast = fast->next->next;
}
fast = slow;
slow = slow->next;
fast->next = NULL;
return mergeLinkList(sortList(head),sortList(slow));
}