19. Remove Nth Node From End of List

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.
使用Linked List 先用一个listnode移过n个 接着两个ListNode同时向后移动即可

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode removeNthFromEnd(ListNode head, int n) {
        ListNode start = new ListNode(0);
        ListNode one = start,two = start;
        two.next = head;

        for(int i = 0; i <= n; i++)
            two = two.next;

        while(two != null){
            one = one.next;
            two = two.next;
            }

        one.next = one.next.next;
        return start.next;
    }
}