合并有序链表C++

/*
    Author: Victor LV
    Date: 2016-9-1 11:20
    Description: C++ list merge(sort)
*/

/**
* C++:将两个升序排列的链表合并成一个升序排列的链表(不开辟新的链表,直接将原链表重新组合) 
* 输入:两个list的头指针
* 返回:新的list头指针 
*/ 

ListNode* find(ListNode *head1, ListNode *head2)
{
    if(head1 == NULL || head2 == NULL)
        return NULL;
    ListNode *newHead = NULL;
    ListNode *p1 = head1;
    ListNode *p2 = head2;
    if(head1->value <= head2->value)
    {
        newHead = head1;
        p1 = p1->next;
    }   
    else
    {
        newHead = head2;
        p2 = p2->next;
    }
    ListNode *ptemp = newHead;
    while(p1 != NULL && p2 != NULL)
    {
        if(p1->value <= p2->value)
        {
            ptemp->next = p1;
            p1 = p1->next;
        }   
        else
        {
            ptemp->next = head2;
            p2 = p2->next;
        }
    }
    while(p1 != NULL)
    {
        ptemp->next = p1;
        p1 = p1->next;
    }
    while(p2 != NULL)
    {
        ptemp->next = p2;
        p2 = p2->next;
    }
    return newHead;
}