【九度OJ】:链表中倒数第K个节点

#include <stdio.h>
#include <stdlib.h>
typedef struct node{
int number;
struct node * next;
}Node;
int getK(Node *link,int k);
int main(){
int n,k,i,temp;
int flag;
while(scanf("%d %d",&n,&k)!=EOF && n>=0 && n<=1000 && k>=0 && k<=1000 ){
Node *link = (Node *)malloc(sizeof(Node));
link->next = NULL;
flag = 0;
Node *tail;
tail = link;
for(i=0;i<n;i++){
scanf("%d",&temp);
Node *n = (Node *)malloc(sizeof(Node));

tail->next = n;
tail = n;
n->number = temp;
}
int numberK = getK(link,k);
numberK ==-1?printf("NULL\n"):printf("%d\n",numberK);
}
return 0;
}
int getK(Node *link,int k){
Node *p1,*p2;
int i;
if(link->next == NULL || k == 0)
return -1;
p1 = link->next;
for(i=1;i<k;i++){
if(p1->next == NULL)
return -1;
p1 = p1->next;
}
p2 = link->next;
while(p1->next!=NULL){
p1 = p1->next;
p2 = p2->next;
}
return p2->number;
}