列表 vector 链表之间的转换

class Solution {
public:
    ListNode *mergeKLists(vector<ListNode *> &lists) {
        int k = lists.size();
        vector<int>nodes;
        for (int i = 0; i < k; i++) {
            ListNode *cur = lists[i];
            while (cur) {
                nodes.push_back(cur->val);
                cur = cur->next;
            }
        }
        sort(nodes.begin(), nodes.end());
        ListNode *cur = new ListNode(0);
        ListNode *res = cur;
        for(int i=0;i<nodes.size();i++){
            cur->next = new ListNode(nodes[i]);
            cur = cur->next;
        }
         return res->next;
    }

};