算法(九) 拆接-拆分

/*
// 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;
        Node cur = head;
        while(cur!=null){
            Node copy = new Node(cur.val);
            copy.next = cur.next;
            cur.next = copy;
            cur = cur.next.next;
        }
      


        Node pre1 = head;
        while(pre1!=null){
            if(pre1.random!=null){
                pre1.next.random = pre1.random.next;
            }
            pre1 = pre1.next.next;
        }

        pre1  = head.next;
        Node pre2 = head.next;
        cur = head;
        while(cur!=null){
            if(cur.next!=null)
                cur.next = cur.next.next;
            else
                cur.next = null;
            if(pre2.next!=null){
                pre2.next = pre2.next.next;
                pre2 = pre2.next;
            }
              
            cur = cur.next;
        }
        return pre1;
    }
}