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	`1`	`+## 题目`
	`2`	`+`
	`3`	`+* 19. 删除链表的倒数第 N 个结点`
	`4`	`+`
	`5`	`+给你一个链表,删除链表的倒数第 n 个结点,并且返回链表的头结点。`
	`6`	`+`
	`7`	`+## 思路`
	`8`	`+快慢指针,快指针先走n步,然后双指针一起走,当快指针到达尾部时,此时慢指针的下一个元素正好是需要删除的元素。`
	`9`	`+`
	`10`	`+## 代码`
	`11`	`+`
	`12`	+```php
	`13`	`+`
	`14`	`+class Solution {`
	`15`	`+`
	`16`	`+ /**`
	`17`	`+ * @param ListNode $head`
	`18`	`+ * @param Integer $n`
	`19`	`+ * @return ListNode`
	`20`	`+ */`
	`21`	`+ function removeNthFromEnd($head, $n) {`
	`22`	`+ $dummy = new ListNode(null);`
	`23`	`+ $dummy->next = $head;`
	`24`	`+`
	`25`	`+ $fast = $slow = $dummy;`
	`26`	`+ for ($i = 0; $i <= $n; $i++) {`
	`27`	`+ $fast = $fast->next;`
	`28`	`+ }`
	`29`	`+`
	`30`	`+ while ($fast !== null) {`
	`31`	`+ $fast = $fast->next;`
	`32`	`+ $slow = $slow->next;`
	`33`	`+ }`
	`34`	`+`
	`35`	`+ $slow->next = $slow->next->next;`
	`36`	`+`
	`37`	`+ return $dummy->next;`
	`38`	`+ }`
	`39`	`+}`
	`40`	`+`
	`41`	+```

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