pta-data structure and algorithm topic set (Chinese)--4-4-based search for chained tables

This requires implementing a function that finds and returns the K-element of the linked table.

function Interface Definition:

ElementType findkth (List L, int K);

Where the list structure is defined as follows:

typedef struct Lnode *ptrtolnode;struct lnode {    ElementType Data;    Ptrtolnode Next;}; typedef ptrtolnode List;

L is given a single linked list, the function findkth to return the K element of the linked table. If the element does not exist, an error is returned.

Example of a referee test procedure:

#include <stdio.h> #include <stdlib.h> #define ERROR-1TYPEDEF int elementtype;typedef struct Lnode * Ptrtolnode;struct Lnode {    ElementType Data;    Ptrtolnode Next;}; typedef ptrtolnode List; List Read (); /* Details are not in this table */elementtype findkth (list L, int K); int main () {    int N, K;    ElementType X;    List L = Read ();    scanf ("%d", &n);    while (n--) {        scanf ("%d", &k);        X = findkth (L, K);        if (x!= ERROR)            printf ("%d", X);        else            printf ("NA");    }    return 0;} /* Your code will be embedded here */

Input Sample:

1 3 4 5 2-163 6 1 5 4 2

Sample output:

4 NA 1 2 5 3

Code

#include <stdio.h> #include <stdlib.h> #define ERROR-1TYPEDEF int elementtype;typedef struct Lnode *    Ptrtolnode;struct Lnode {ElementType Data; Ptrtolnode Next;}; typedef ptrtolnode List; List Read ();    /* Details are not in this table */elementtype findkth (list L, int K); int main () {int N, K;    ElementType X;    List L = Read ();    scanf ("%d", &n);        while (n--) {scanf ("%d", &k);        X = findkth (L, K);        if (x!= ERROR) printf ("%d", X);    else printf ("NA"); } return 0;}  List Read () {int num = 0;  scanf ("%d", &num);  if (-1 = = num) {return NULL;  } List List = (list) malloc (sizeof (struct lnode));  List last = list;  List->data = num;    List->next = NULL;  scanf ("%d", &num);    while (-1! = num) {ptrtolnode node = (List) malloc (sizeof (struct lnode));    Node->data = num;    Node->next = NULL;    Last->next = node;    last = node;  scanf ("%d", &num); } return list;} Returns the K of a linked tableElements.  If the element does not exist, returns Errorelementtype findkth (List L, int K) {if (NULL = = L) {return ERROR;  } if (K <= 0) {return ERROR;  } ptrtolnode node = L;  int i = 1;    while (NULL! = node && i < K) {//printf ("data =%d\n", node->data);    if (NULL = = Node->next) {break;    } node = node->next;  i++;  } if (i< K) {return ERROR;  }else{return node->data; }}

pta-data structure and algorithm topic set (Chinese)--4-4-based search for chained tables