83. Remove Duplicates from Sorted List

题意： Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,Given 1->1->2, return 1->2.Given 1->1->2->3->3, return 1->2->3. 

代码：

def deleteDuplicates(self, head):        """        :type head: ListNode        :rtype: ListNode        """        # h = ListNode(float('-inf'))        # h.next = head        if not head:            return head        p = head        while p.next:            # print p.val            if p.val == p.next.val:                 p.next = p.next.next            else:                p = p.next        return head

参考代码：

def deleteDuplicates(self, head):    cur = head    while cur:        while cur.next and cur.next.val == cur.val:            cur.next = cur.next.next     # skip duplicated node        cur = cur.next     # not duplicate of current node, move to next node    return head

还有一个递归的code:

def deleteDuplicates(self, head):        """        :type head: ListNode        :rtype: ListNode        """        if not head or not head.next:            return head        head.next = self.deleteDuplicates(head.next)        return head.next if head.val == head.next.val else head