【LeetCode热题100】【链表】合并 K 个升序链表

class Solution {
public:
    ListNode *mergeKLists(vector<ListNode *> &lists) {
        int min = INT_MAX, index = -1;
        for (int i = 0; i < lists.size(); ++i) {
            if (lists[i] && lists[i]->val < min) {
                min = lists[i]->val;
                index = i;
            }
        }
        if (index == -1)
            return nullptr;
        ListNode *head = lists[index];
        lists[index] = lists[index]->next;
        head->next = mergeKLists(lists);
        return head;
    }
};