MergeKSortedLists_CColunmn.cpp

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* mergeKLists(vector<ListNode*>& lists) {
        int len_l = lists.size();
        ListNode head(0);
        ListNode *h = &head;
        while(true){
            bool isBreak = true;
            int minVal = INT_MAX;
            int min_index = 0;
            for(int i = 0; i < len_l; i++)
            {
                if(lists[i] != NULL){
                    isBreak = false;
                    if(lists[i]->val <= minVal)
                    {
                        min_index = i;
                        minVal = lists[i]->val;
                    }
                }
            }
            
            if(isBreak)
                break;
            
            h->next = lists[min_index];
            h = h->next;
            lists[min_index] = lists[min_index]->next;
        }
        return head.next;
    }
};