复杂链表的复制

我的题解

/*
// Definition for a Node.
class Node {
    int val;
    Node next;
    Node random;

    public Node(int val) {
        this.val = val;
        this.next = null;
        this.random = null;
    }
}
*/
class Solution {
    public Node copyRandomList(Node head) {
        if(head==null) return null;
        Node tmp = head,headA,headB;
        headA =new Node(head.val);
        headB=headA;
        while(tmp!=null){//安排好next指针（先让节点连起来）
           tmp=tmp.next;
           if(tmp==null) break; 
           Node cur =new Node(tmp.val);
           headA.next=cur;
           headA=cur;
        }
        tmp=head;
        Node cur=headB;
       
        while(tmp!=null){//安排random指针
            //初始化数据
            int i=0,j=0;
            headA=headB;
            Node tmp1=head;
            while(tmp1!=null){//双重循环确定每一个节点的random指向的位置（用计数器记录）
                if(tmp.random==null){
                    i=-1;break;
                } 
                i++;
                if(tmp.random==tmp1){
                    break;
                }
                tmp1=tmp1.next;
            }
            
            while(headA!=null){
            if(i==-1) break;
             j++;
             if(i==j){//移动到之前计数的相同位置直接进行指向
                 cur.random=headA;
                 break;
             }
             headA=headA.next;
            }
            tmp=tmp.next;
            cur=cur.next;
        }
        return headB;
    }
}

官方题解

/*
// Definition for a Node.
class Node {
    int val;
    Node next;
    Node random;

    public Node(int val) {
        this.val = val;
        this.next = null;
        this.random = null;
    }
}
*/
class Solution {
    public Node copyRandomList(Node head) {
        if(head == null) return head;
        Map<Node,Node> m = new HashMap<>();
        Node cur = head;
        while(cur != null){
            m.put(cur,new Node(cur.val));
            cur = cur.next;
        }
        cur = head;
        while(cur != null){
            m.get(cur).next = m.get(cur.next);
            m.get(cur).random = m.get(cur.random);
            cur = cur.next;
        }
        return m.get(head);

    }
}