JZ76 删除链表中重复的结点

JZ76 删除链表中重复的结点

删除链表中重复的结点_牛客题霸_牛客网 (nowcoder.com)

import java.util.*;
public class Solution {
    public ListNode deleteDuplication(ListNode head) {
        if(head==null){
            return null;
        }
        ListNode newHead=new ListNode(-1);
        newHead.next=head;
        ListNode cur=newHead;
        while(cur.next!=null&&cur.next.next!=null){
            if(cur.next.val==cur.next.next.val){
                int tmp=cur.next.val;
                while(cur.next!=null&&cur.next.val==tmp){
                    cur.next=cur.next.next;
                }
            }else{
                cur=cur.next;
            }
        }
        return newHead.next;
    }
}


//map
import java.util.*;
import java.util.HashMap;
public class Solution {
    public ListNode deleteDuplication(ListNode head) {
        if(head==null){
            return null;
        }
        HashMap<Integer,Integer> map=new HashMap<>();
        ListNode cur=head;
        while(cur!=null){
            if(map.containsKey(cur.val)){
                map.put(cur.val,map.get(cur.val)+1);
            }else{
                map.put(cur.val,1);
            }
            cur=cur.next;
        }
        ListNode newHead=new ListNode(-1);
        newHead.next=head;
        cur=newHead;
        while(cur.next!=null){
            if(map.get(cur.next.val)!=1){
                cur.next=cur.next.next;
            }else{
                cur=cur.next;
            }
        }
        return newHead.next;
    }
}