/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可
     *
     * 
     * @param lists ListNode类vector 
     * @return ListNode类
     */
    public: struct compare{
        bool operator()(int a,int b){
            return a>b;
        }
    };
    ListNode* mergeKLists(vector<ListNode*>& lists) {
        // write code here
        ListNode* ans=new ListNode(-1),*ans1=ans;
        int minList;
        priority_queue<int, vector<int>, compare> setLists;
        for(auto i:lists){
            while(i!=nullptr){
                setLists.push(i->val);
                i=i->next;
            }
        }
        while(!setLists.empty()){
            ans1->next=new ListNode(setLists.top());
            ans1=ans1->next;
            setLists.pop();
        }
        return ans->next;
    }
};