复制含有随机指针节点的链表

2019独角兽企业重金招聘Python工程师标准>>>

 

复制含有随机指针节点的链表

给定一个由Node节点类型组成的无环单链表的头节点head,写一个函数完成这个链表中所有结构的复制，并返回复制的新链表的头节点。

 

 

 

package com.javause.Algorithm.copyRandomNodeList;

 

import java.util.HashMap;

 

public class CopyListWithRand {

  public class Node {

    public int value;

    public Node next;

    public Node rand;

 

    public Node(int data) {

      this.value = data;

    }

  }

 

  public Node copyListWithRand1(Node head) {

    HashMap<Node, Node> map = new HashMap<Node, Node>();

    Node cur = head;

    while (cur != null) {

      map.put(cur, new Node(cur.value));

      cur = cur.next;

    }

 

    cur = head;

 

创建指针next,

    while (cur != null) {

      map.get(cur).next = map.get(cur.next);

      map.get(cur).rand = map.get(cur.rand);

      cur = cur.next;

    }

    return map.get(head);

  }

 

  public Node copyListWithRand2(Node head) {

    if (head == null) {

      return null;

    }

    Node cur = head;

    Node next = null;

    // 复制并连接每一个节点

    while (cur != null) {

      next = cur.next;

      cur.next = new Node(cur.value);

      cur.next.next = next;

      cur = next;

    }

    cur = head;

    Node curCopy = null;

    // 设置复制节点的rand指针

    while (cur != null) {

      next = cur.next.next;

      curCopy = cur.next;

      curCopy.rand = cur.rand != null ? cur.rand.next : null;

      cur = next;

    }

    Node res = head.next;

    cur = head;

    // 拆分

    while (cur != null) {

      next = cur.next.next;

      curCopy = cur.next;

      cur.next = next;

      curCopy.next = next != null ? next.next : null;

      cur = next;

    }

    return res;

 

  }

}

 

转载于:https://my.oschina.net/iioschina/blog/1517532