Leetcode---k个一组翻转链表

以你之姓@ 2022-04-22 02:20 161阅读 0赞

初步代码，有时间优化下= =

/**
     * Definition for singly-linked list.
     * public class ListNode {
     *     int val;
     *     ListNode next;
     *     ListNode(int x) { val = x; }
     * }
     */
    class Solution {
        public ListNode reverseKGroup(ListNode head, int k) {
              if(head==null||head.next==null){
                return head;
            }
            ListNode tmp=head;
            ListNode result=null ;
            int i=0,j=1;
            ListNode cur = head;
            ListNode prev = null;
            ListNode tmp1 = null;
            ListNode tmp2 = head; //储存一组中最后一个
            ListNode nextF=head;
            while (tmp2.next!=null){
                nextF=tmp;
                while (i<k){
                    if(nextF!=null&&nextF.next!=null&&nextF.next.next!=null){
                        if(i+1<k){
                            nextF=nextF.next.next;
                        }else {
                            nextF=nextF.next;
                        }
                    }else{
                        if(i+1==k&&nextF!=null&&nextF.next!=null){
                            nextF=nextF.next;
                        }else{
                            nextF=null;
                        }
                    }
                    tmp=tmp.next;
                    i++;
                    if(tmp==null){
    
                        break;
                    }                
                }
                if(i<k){  //3
                    break;
                }
                i=0;       
                tmp2=cur;
                while (cur != tmp&&cur != null) {
                    tmp1 = cur.next;  //2
                    cur.next = prev;  //1.next=null 2.next=1
                    prev = cur;     // prev=1  2
                    cur = tmp1;    //cur = 2 3
                }
                if(j==1){
                    result=prev;
                }
                if(nextF!=null){
                    tmp2.next=nextF;
                }else {
                    tmp2.next=tmp;
                }
                j++;
            }
    
            if(result==null){
                return head;
            }
    
            return result;
        }
    }