Solution.java

package _019;

import structure.ListNode;

/**
 * <pre>
 *     author: Blankj
 *     blog  : http://blankj.com
 *     time  : 2017/04/27
 *     desc  :
 * </pre>
 */
public class Solution {
    public ListNode removeNthFromEnd(ListNode head, int n) {
        ListNode pre = head;
        ListNode afterPreN = head;
        while (n-- != 0) {
            afterPreN = afterPreN.next;
        }
        if (afterPreN != null) {
            while (afterPreN.next != null) {
                pre = pre.next;
                afterPreN = afterPreN.next;
            }
            pre.next = pre.next.next;
        } else {
            head = head.next;
        }
        return head;
    }

    public static void main(String[] args) {
        Solution solution = new Solution();
        ListNode.print(solution.removeNthFromEnd(ListNode.createTestData("[1,2,3,4,5]"), 2));
        ListNode.print(solution.removeNthFromEnd(ListNode.createTestData("[1]"), 1));
    }
}