0021-merge-two-sorted-lists.cpp

class Solution {
public:
    ListNode* mergeTwoLists(ListNode* list1, ListNode* list2) {
        ListNode* dummy = new ListNode(0);
        ListNode* cur = dummy;

        while (list1 && list2) {
            if (list1->val > list2->val) {
                cur->next = list2;
                list2 = list2->next;
            } else {
                cur->next = list1;
                list1 = list1->next;
            }
            cur = cur->next;
        }

        cur->next = list1 ? list1 : list2;

        return dummy->next;        
    }
};