23. 合并K个排序链表

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    
    
    public int findMin(ListNode[] lists){
        
        int min = 0x7ffffff;
        int index = -1;
        for( int i=0; i < lists.length; ++i ){
            if( lists[i] == null )
                continue;
            
            if( lists[i].val < min ){
                min = lists[i].val;
                index = i;
            }
        }
        
        return index;
        
    }
    
    public ListNode mergeKLists(ListNode[] lists) {
        
        ListNode head = new ListNode(0);
        ListNode tmp =head;
        int i;
        while( true ){ 
            i = findMin(lists);
            if( i == -1 )
                break;
            tmp.next = lists[i];
            tmp = lists[i];
            lists[i] = lists[i].next;
        }
        return head.next;
    }
}