合并k个已排序的链表

Posted 2022-12-16 唐 昊

采用逐步遍历

 public ListNode mergeKLists(ArrayList<ListNode> lists) 
        ListNode root = new ListNode(-1);
       
        for(int i = 0 ;i< lists.size();i++)
            root.next = mergeTwoLists(root.next,lists.get(i));
        
        return root.next;
    
    
    
    private ListNode mergeTwoLists(ListNode head1,ListNode head2)
    
        if(head1 == null || head2 == null)
            return head1==null?head2:head1;
        
        ListNode root = new ListNode(-1);
        ListNode temp = root;
        while(head1 != null && head2 != null)
            
            if(head1.val > head2.val)
                temp.next = head2;
                temp = temp.next;
                head2 = head2.next;
            
            else
            
                 temp.next = head1;
                temp = temp.next;
                head1= head1.next;
            

        
        if(head1 != null)
            temp.next = head1;
           
        
        else
            temp.next = head2;
           
        
        return root.next;