力扣 19. 删除链表的倒数第 N 个结点
题目描述：
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。
解析：
双指针：图片是删除倒数第二个节点
Java:
public ListNode removeNthFromEnd(ListNode head, int n) {
ListNode dummy = new ListNode(0);
dummy.next = head;
ListNode n1 = dummy;
ListNode n2 = dummy;
for(int i = 0; i <= n; i++) {
n2 = n2.next;
}
while(n2 != null) {
n1 = n1.next;
n2 = n2.next;
}
n1.next = n1.next.next;
return dummy.next;
}JavaScript:
var removeNthFromEnd = function(head, n) {
let dummy = new ListNode();
dummy.next = head;
let n1 = dummy;
let n2 = dummy;
for(let i = 0; i <= n; i++) {
n2 = n2.next;
}
while(n2 !== null) {
n1 = n1.next;
n2 = n2.next;
}
n1.next = n1.next.next;
return dummy.next;
};
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