leetcode-剑指25-OK

同leetcode的21
address

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */


struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2){
    int getval(struct ListNode* node){
        return node->val;
    }
    if(l1 == NULL)
        return l2;
    if(l2 == NULL)
        return l1;
    struct ListNode *head,*p;
    if(getval(l1)<getval(l2)){
        head = l1;
        l1 = l1->next;
    }else{
        head = l2;
        l2 = l2->next;
    }
    p = head;
    while(l1&&l2){
        if(getval(l1)<getval(l2)){
            p->next = l1;
            l1 = l1->next;
        }else{
            p->next = l2;
            l2 = l2->next;
        }
        p = p->next;
    }
    if(l1)
        p->next = l1;
    if(l2)
        p->next = l2;
    return head;
}