leetcode/code/lc19.java at master · mJackie/leetcode · GitHub

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package code;

* 19. Remove Nth Node From End of List

* 题意：删除链表中倒数第n个节点

* 难度：Medium

* 分类：Linked List, Two Pointers

* 思路：快慢指针，快指针达到链表尾部时，慢指针所在位置即为操作的节点

* 注意：看清题意，是倒数第n个，且复杂度为n

public class lc19 {

public ListNode removeNthFromEnd(ListNode head, int n) {

ListNode low = new ListNode(0);

ListNode fast = new ListNode(0);

ListNode res = low;

low.next = head;

fast.next = head;

while(n>0){

fast = fast.next;

n--;

}

while(fast.next!=null){

low = low.next;

fast = fast.next;

}

ListNode temp = low.next.next;

low.next = temp;

return res.next;

}

public class ListNode {

int val;

ListNode next;

ListNode(int x) { val = x; }

}

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