王道书P41 T22（单链表实现）

#include 
#include 

typedef struct LNode{
    int data;
    struct LNode* next;
}LNode,*LinkList;

int FindDk(LinkList L,int k){
    LinkList p = L -> next;
    int count = 1;
    while(count++ <= k){
        p = p -> next;
    }
    LinkList q = L -> next;
    while(p){
        p = p -> next;
        q = q -> next;
    }
    return q -> data;
}

//补充
int FindMid(LinkList L){
    LinkList fast = L -> next;
    LinkList slow = L -> next;
    while(fast && fast -> next){
        fast = fast -> next -> next;
        slow = slow -> next;
    }
    return slow -> data;
}