LetCode 23. 合并K个排序链表

static int __ = [](){
	std::ios::sync_with_stdio(false);
	cin.tie(nullptr);
	return 0;
}();
/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */

// log(n)*n;
class Solution {
public:
    ListNode* mergeKLists(vector<ListNode*>& lists) {
        if (lists.size() <= 0)
            return NULL;
        ListNode* res = new ListNode(0);
        ListNode* list = res;
        priority_queue<int,vector<int>,greater<int>> q;
        
        for (int i = 0; i < lists.size(); i++){
            ListNode* index = lists[i];
            while(index != NULL){
                q.push(index->val);
                index = index->next;
            }
        }
        
        while(!q.empty())
            list->next = new ListNode(q.top()), list = list->next, q.pop();
        return res->next;
    }
};