递归合并链表~

#include<iostream>
#include<map>
using namespace std;

class node{
public:
    node():value(0),next(NULL){}
    ~node(){}
    int value;
    node* next;
};///be careful this ;


node* createlist(int a[],int n)
{
 node* startnode = new node[n];
 node* ret = startnode;
 for(int i = 0;i<n;i++)
 {
     startnode[i].value = a[i];
     if(i<n-1) 
         startnode[i].next = startnode + i + 1;
 }
 return ret;
}

node* helper(node * head1,node* head2) ///这种问题都可以试着用递归来计算，好像方便的多~
{
  if(head1 == NULL) return head2;
  if(head2 == NULL) return head1;     ///多想想递归~~~
  node* head;
  if(head1->value<head2->value)
  {
   head = head1;
   head->next = helper(head1->next,head2);
  }else
  {
   head = head2;
   head->next = helper(head1,head2->next);
  }
  return head;
}

int main()
{
    int a[] = {1,3,5,7,9};
    int b[] = {2,4,6,8,10};
    node * t1 = createlist(a,sizeof(a)/sizeof(a[0]));
    node * t2 = createlist(b,sizeof(b)/sizeof(b[0]));
    node * head = helper(t1,t2);
    while(head)
    {cout<<" "<<head->value; head = head->next;}
}