链表中倒数第k个节点

题目描述

输入一个链表，输出该链表中倒数第k个结点。

 

/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode FindKthToTail(ListNode head,int k) {
        ListNode dummy = new ListNode(0);
        if (k == 0) return null;
        dummy.next = head;
        ListNode p1 = dummy, p2 = dummy;
        int i = 0;
        while (p1.next != null && i < k - 1) {
            p1 = p1.next;
            i++;
        }
        if (p1.next == null) {
            return null;
        } 
        
        
        while (p1.next != null) {
            p1 = p1.next;
            p2 = p2.next;
        }
        return p2;
            
    }
}