查找单链表的倒数第k个节点，要求只能遍历一次链表

单链表排序
查找单链表的倒数第k个节点，要求只能遍历一次链表
函数原型LinkList FindLastKNode(LinkList L, int k)

#define _CRT_SECURE_NO_WARNINGS 1typedef int DataType;#define NULL 0#include<stdio.h>#include<windows.h>#include<assert.h>

typedef struct Node
{
DataType data;
struct Node*next;
}Node, *LinkList;
void InitList(LinkList *L)
{
L = (Node)malloc(sizeof(Node));
if (*L == NULL){
printf(“申请内存空间失败”);
}
(*L)->next = NULL;
(*L)->data = NULL;
}
LinkList BuyNode(DataType data)
{
LinkList NewNode = NULL;
NewNode = (LinkList)malloc(sizeof(Node));
if (NewNode == NULL){
printf(“为节点创建空间失败”);
}
NewNode->data = data;
NewNode->next = NULL;
return NewNode;
}
void PrintList(LinkList L)
{
LinkList Cur = L;
if (L == NULL){
printf(“NULL”);
}
while (Cur)
{
printf(“%d—>”, Cur->data);
Cur = Cur->next;
}
printf(“NULL\n”);
}
void PushBack(LinkList* L, DataType data)
{
assert(L);
LinkList Cur = *L;
if (Cur == NULL){
Cur = BuyNode(data);
}
while (Cur->next)
{
Cur = Cur->next;
}
Cur->next = BuyNode(data);
}
LinkList FindLastKNode(LinkList L, int k)
{
LinkList Fast = L;
LinkList Slow = L;

if (L == NULL || k <= 0)    return NULL;while (k--){    if (Fast == NULL){        return NULL;    }    Fast = Fast->next;}while (Fast){    Fast = Fast->next;    Slow = Slow->next;}return Slow;

}
test3()
{
LinkList L = NULL;
InitList(&L);
PushBack(&L, 2);
PushBack(&L, 4);
PushBack(&L, 6);
LinkList S=FindLastKNode(L, 2);
printf(“%d”,S->data);
}
int main()
{
test3();
system(“pause”);
return 0;
}“`