/**
knakul853
 */
class Solution {
public:
    ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {

        if(!l1)return l2;
        if(!l2)return l1;
        if(l1->val <= l2->val)
        {
            l1->next = mergeTwoLists(l1->next , l2);
            return l1;
        }
        else
        {
            l2->next = mergeTwoLists(l1, l2->next);return l2;
        }


    }
};

class Solution {
public:
    ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {

        if(!l1)return l2;
        if(!l2)return l1;
        if(l1->val <= l2->val)
        {
            l1->next = mergeTwoLists(l1->next , l2);
            return l1;
        }
        else
        {
            l2->next = mergeTwoLists(l1, l2->next);return l2;
        }


    }
};