lintcode-medium-Copy List with Random Pointer

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.

Return a deep copy of the list.

思路:

先按照正常顺序,得到复制的链表,同时用一个HashMap建立新旧节点的对应关系,再把random pointer加入,这样可以保证random pointer指向的节点永远都是已经建立的新节点,不会是null

/**
 * Definition for singly-linked list with a random pointer.
 * class RandomListNode {
 *     int label;
 *     RandomListNode next, random;
 *     RandomListNode(int x) { this.label = x; }
 * };
 */
public class Solution {
    /**
     * @param head: The head of linked list with a random pointer.
     * @return: A new head of a deep copy of the list.
     */
    public RandomListNode copyRandomList(RandomListNode head) {
        // write your code here
        if(head == null)
            return null;

        RandomListNode newhead = new RandomListNode(head.label);
        RandomListNode p1 = head.next;
        RandomListNode p2 = newhead;
        HashMap<RandomListNode, RandomListNode> map = new HashMap<RandomListNode, RandomListNode>();
        map.put(head, newhead);

        while(p1 != null){
            p2.next = new RandomListNode(p1.label);
            p2 = p2.next;
            map.put(p1, p2);
            p1 = p1.next;
        }

        p1 = head;
        p2 = newhead;

        while(p1 != null){
            p2.random = map.get(p1.random);
            p1 = p1.next;
            p2 = p2.next;
        }

        return newhead;
    }
}
时间: 2024-10-07 13:42:33

lintcode-medium-Copy List with Random Pointer的相关文章

LintCode - Copy List with Random Pointer

LintCode - Copy List with Random Pointer LintCode - Copy List with Random Pointer Web Link Description Code - C Tips Web Link http://www.lintcode.com/en/problem/copy-list-with-random-pointer/ Description A linked list is given such that each node con

【LeetCode】Copy List with Random Pointer

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. 思路:第一遍正常复制链表,同时用哈希表保存链表中原始节点和新节点的对应关系,第二遍遍历链表的时候,再复制随机域. 这是一种典型的空间换时间的做法,n个节点,需要大小为O(n

Copy List with Random Pointer

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. /** * Definition for singly-linked list with a random pointer. * struct RandomListNode

LeetCode: Copy List with Random Pointer [138]

[题目] A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. [题意] 给定一个链表,每个节点除了next指针外,还有一个random指针,指向任意的节点. 要求,复制这样的一个链表 [思路] 思路1: 先一次生成每个节点对

[leetcode]Copy List with Random Pointer @ Python

原题地址:https://oj.leetcode.com/problems/copy-list-with-random-pointer/ 题意: A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. 解题思路:这题主要是需要深

Copy List with Random Pointer leetcode java

题目: A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. 题解: 如果要copy一个带有random pointer的list,主要的问题就是有可能这个random指向的位置还没有被copy到,所以解决方法都是多次扫描li

133. Clone Graph 138. Copy List with Random Pointer 拷贝图和链表

133. Clone Graph Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors. OJ's undirected graph serialization: Nodes are labeled uniquely. We use # as a separator for each node, and , as a separator for node lab

[LeetCode][JavaScript]Copy List with Random Pointer

Copy List with Random Pointer A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. https://leetcode.com/problems/copy-list-with-random-poin

[Leetcode][JAVA] Clone Graph, Copy List with Random Pointer

Clone Graph: Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors. OJ's undirected graph serialization: Nodes are labeled uniquely. We use # as a separator for each node, and , as a separator for node label a

leetcode_138_ Copy List with Random Pointer

欢迎大家阅读参考,如有错误或疑问请留言纠正,谢谢  Copy List with Random Pointer A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. 算法分为三步: 1. copy and insert 2.