Remove Nth Node From End of List

• Given a linked list, remove the nth node from the end of list and return its head.

• For example,

  Given linked list: 1->2->3->4->5, and n = 2.

  After removing the second node from the end, the linked list becomes 1->2->3->5.

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  主要考察链表指针的操作以及对边界异常情况的处理，C++代码如下：

class Solution {public:    ListNode *removeNthFromEnd(ListNode *head, int n) {    ListNode *pNodeOne = head, *pNodeTwo = head;    while (pNodeTwo != NULL) {        pNodeTwo = pNodeTwo->next;        if (n-- < 0)             pNodeOne = pNodeOne->next;    }    if (n == 0)         head = head->next;    else         pNodeOne->next = pNodeOne->next->next;    return head;    }};