Day 13 访问链表第i个节点

class ListNode:
    def __init__(self,x):
        self.val = x
        self.next = None

    def getiNodex(self, head,n,i):
        '''
        head:链表头结点
        n:链表长度
        i:返回第i个节点node i
        '''
        if i < 0 or  i > n-1:
            raise Exception('超出索引')
        p = self.head
        for cur in range(i):
            p = p.next
        return p