Home LeetCode. 23. Merge k Sorted Lists
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LeetCode. 23. Merge k Sorted Lists

image

[Link] https://leetcode.com/problems/merge-k-sorted-lists/


Slow runtime…Can improve this by unsing priorityque.

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/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode mergeKLists(ListNode[] lists) {
      ListNode curNode = new ListNode();
      ListNode initNode = curNode;
      int min;

      while(true) {
        ListNode minNode = new ListNode(Integer.MAX_VALUE);
        int minIdx = -1;
        for(int i = 0; i < lists.length; i++) {
          ListNode node = lists[i];
          if(node == null) continue;
          if(minNode.val > node.val) {
            minNode = node;
            minIdx = i;
          }
        }
        if(minIdx >= 0) {
          curNode.next = minNode;
          lists[minIdx] = lists[minIdx].next;
        }
        else break;
        curNode = curNode.next;
      }
      return initNode.next;
    }
}
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