已知两个链表head1 和head2 各自有序，请把它们合并成一个链表依然有序

递归比较两个链表的头部

<span style="font-size:18px;">#include <iostream>
#include <string.h>
struct node
{    
    int data;
    node *next;
};
node *MergeRecursive(node *head1, node *head2)
{
    node *head = NULL;
    if (head1 == NULL)
    {
        return head2;
    }
    if (head2 == NULL)
    {
        return head1;
    }
    if (head1->data < head2->data)
    {
        head = head1 ;
        head->next = MergeRecursive(head1->next,head2);
    }
    else
    {
        head = head2 ;
        head->next = MergeRecursive(head1,head2->next);
    }
    return head ;
}
</span>

我采用的是递归方法，还有非递归的方法。