删除单向链表中的重复结点

完成函数dubdel的编写，该函数删除单向链表中的重复结点，如果链表中存在重复结点（除next指针外的其它数据成员的值相同）时，保留离链首最近的结点。

样例输入：

5
1 2 3 2 4

样例输出：

1 2 3 4

#include<iostream>
#include <string>
using namespace std;
struct Node 
{
    int num;
    Node *next;
};
Node * dubdel(Node *head)
{
 int a[1000],n=0,i;
 Node *cur=head,*pre=NULL;
 while(cur)
 {
  bool del=false;
  for(i=0;i<n;i++)
  {
   if(a[i]==cur->num)
   {
    del=true;
    break;
   }
  }
  if(del)
  {
   pre->next=cur->next;
   delete cur;
   cur=pre->next;
  }
  else
  {
   a[n++]=cur->num;
   pre=cur;
   cur=cur->next;
  }
  } 
  return head;
}
void deleteList(Node *head)
{
    Node *tmp;
    while (head)
    {
        tmp = head->next;
        delete head;
        head = tmp;
    }
}
void printList(Node *head)
{
    while(head)
    {
        cout<<head->num<<" ";
        head = head->next;
    }
    cout<<endl;
}
Node * createList(int a[], int len)
{
    Node *head = NULL;
    if(len<1)
        return head;
    for(int i = len - 1; i >= 0; i--)
    {
        Node *tmp = new Node;
        tmp->num = a[i];
        tmp->next = head;
        head = tmp;
    }
    return head;
}
int main()
{
    int len;
    cin>>len;
    int s[len];
    for(int j = 0; j < len; j++)
    {
        cin>>s[j];
    }
    Node * head = createList(s,len);
    head = dubdel(head);
    printList(head);
    deleteList(head);
    return 0;
}