對鏈接列表進行插入排序時遇到問題。 當我嘗試按升序對列表進行排序時，僅打印列表的第一個值

Question

我正在為我的一個班級編寫一個程序，並被困在要求按升序對鏈表進行排序的部分。 我試圖對列表進行排序，但是當我運行該函數時，它只打印第一個值。 我知道打印功能有效，因為我可以在沒有插入排序的情況下運行它，並且打印效果很好。

我的代碼如下：

#include "linkedList.h"
#include <stdlib.h>
#include <stdio.h>


void swap(struct Link *first, struct Link *second){
  struct Link* temp = first;
  temp->next = first->next;
  temp->value = first->value;
  first = second;
  first->next = second->next;
  first->value = second->value;
  second = temp;
  second->next = temp->next;
  second->value = temp->value;
}

struct Link* listInsertionSort(struct Link* head) {

  /*
   * This function should perform an insertion sort on the list whose head is
   * provided as the function's argument, so that the values in the list are
   * sorted in ascending order, starting at the head.
   *
   * The sort should be done without allocating any new Link structs or any
   * other auxiliary data structures.
   *
   * Return a pointer to the new head of the list.
   */

struct Link* cur = head;
cur->next = head->next;
struct Link* count;
for(;cur->next != NULL; cur = cur->next){
  for(count = cur->next; count != NULL; count = count->next){
      if(cur->value < count->value){
        swap(cur, count);
      }
  }
}


return cur;

}

而linkedList.h 文件在這里：

#ifndef __LINKEDLIST_H
#define __LINKEDLIST_H

#define TYPE int

/* Single link structure */
struct Link {
  TYPE value;
  struct Link* next;
};

struct Link* listInsertionSort(struct Link* head);
struct Link* reverseList(struct Link* head);
struct Link* reverseListRecursive(struct Link* head);

#endif

測試文件在這里（雖然這里不應該有任何錯誤，因為這是我們的老師提供給班上所有學生的）：

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <float.h>

#include "linkedList.h"

struct Link* buildLink(int n, int rev, int mod) {
  struct Link* head = (struct Link*)malloc(sizeof(struct Link));
  struct Link* cur = head;

  for (int i = 0; i < n; i++) {
    if (rev)
      cur->value = n - i - 1; //If rev is 1, creates list from high value to low value
    else
      cur->value = i; //If rev is 0, creates list from low value to high value

    if (mod)
      cur->value = cur->value % mod; //Modifies list so that it increments up to value of mod

    if (i + 1 < n)
      cur->next = (struct Link*)malloc(sizeof(struct Link)); //Creates next link in the array
    else
      cur->next  = 0; //If less than the cap it sets next character to NULL, ending the list
    cur = cur->next; //Sets current link to next link to continue for loop
  }

  return head;
}

void printLL(struct Link* l,char* s) {
  printf("LL %s: ",s);
  while (l != 0) {
    printf("%d ", l->value);
    l = l->next;
  }
  printf("\n");
}

int main() {
  // We aren't practicing good memory management
  //    here....
  struct Link* l = buildLink(10, 0, 4);
  struct Link* r = listInsertionSort(l);
  printLL(r, "Sort 0-9 mod 4"); //This should print 0 0 0 1 1 1 2 2 3 3

}

有誰知道這里的問題是什么？ 錯誤出現在 listInsertionSort(struct Link* head) 中，但我嘗試了多種不同的組合但沒有成功。

當前輸出是：LL Sort 0-9 mod 4:1 什么時候應該是：LL Sort 0-9 mod 4: 0 0 0 1 1 1 2 2 3 3

Answer 1

我找到了解決我遇到的問題的方法。

而不是返回 cur ，我應該返回 head 。 我還更改了交換函數，使其不包括列表中鏈接的交換值，因為這是不必要的並且看起來很混亂。