🌕 剑指 Offer 35. 复杂链表的复制

难度: 🌕

问题描述

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解法

/*
// 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) {
        // 思路：
        // HashMap 存储 原节点 - 新节点
        if(head == null) {
            return null;
        }
        HashMap<Node, Node> map = new HashMap<>();
        Node res = new Node(-1);
        Node pre = res;
        Node cur = head;
        while(cur != null) {
            Node node = new Node(cur.val); // 新复制节点
            map.put(cur, node);
            pre.next = node;
            pre = node;
            cur = cur.next;
        }
        // 填充 rand 节点
        cur = head;
        while(cur != null) {
            if(cur.random != null) {
                Node origRand = cur.random;
                Node node = map.get(cur);
                Node rand = map.get(origRand);
                node.random = rand;
                // System.out.println(cur.val + "  " + origRand.val + "  " + node.val + "  " + rand.val);
            }
            cur = cur.next;
        }
        return res.next;
    }
}

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输出