题解 | #输出单向链表中倒数第k个结点#

import java.util.Scanner;



public class Main {
    public static class ListNode{
    int val;
    ListNode next;
    ListNode(int val){
        this.val=val;
    }
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while(in.hasNext()){
            int n=in.nextInt();
            ListNode h=new ListNode(in.nextInt());
            ListNode p=h;
            for(int i=1;i<n;i++){
                p.next=new ListNode(in.nextInt());
                p=p.next;
            }
            int k=in.nextInt();
            System.out.println(fromHead(h,k));
        }
        
        
    }
    public static int fromHead(ListNode h,int k){
        ListNode q=h;
        int count=1;//注意初始是1，因为链表不为空
        while(q.next!=null){
            count++;
            q=q.next;
        }
        if(count==1){
            return q.val;
        }
        q=h;
        for(int i=1;i<=count ;i++){
            if(i==count+1-k){
                return q.val;
            }
            q=q.next;
        }
        return 0;
    }
}