算法（22）-复制含随机指针的单链表-C++

 

单链表结构如下：两个节点 对象指针。
 

class Noderand
{
public:
	int m_value;
	Noderand * next;
	Noderand * rand;
	Noderand(int value);

};
Noderand::Noderand(int value)
{
	m_value = value;
}

思路：用hashMap key-value  老、新节点。
           1.遍历一次生成map 从左到右
            2.再遍历一次        从左到右
上代码

class NodeRandom {
public:
	int value;
	NodeRandom *next;
	NodeRandom *rand;
	 NodeRandom(int data) {
		value = data;
	}
};
NodeRandom* copyListWithRand(NodeRandom *head) 
{
	unordered_map<NodeRandom*, NodeRandom*> map;
	NodeRandom *cur = head;
	while (cur !=NULL)                            //1.遍历生成哈希表
	{
		map.insert(make_pair(cur, new NodeRandom(cur->value)));
		cur = cur->next;
	}
	cur = head;
	while (cur != NULL)                          //2.再遍历一遍，重新赋值 赋值的是 NodeRandom* 类型
	{
		map.find(cur) = map.find(cur->next); //哈希表查找
		map.find(cur) = map.find(cur->rand);
		cur = cur->next;
	}
	return map.find(head)->first;
}

void printRandLinkedList(NodeRandom* head) 
{
	NodeRandom *cur = head;
	cout<<"order: "<<endl;
	while (cur!= NULL) {
		cout << cur->value<<",";
		cur = cur->next;
	}
	cout << endl;
	cur = head;
	cout << "rand:  " << endl;
	while (cur != NULL) 
	{
		if(cur->rand == NULL)
		{
			cout << "-,";
		}
		else
		{
			cout << cur->rand->value<<",";
		}
		cur = cur->next;
	}
	cout << endl;
}

void CopyListWithRandom_test()
{
	NodeRandom* head = NULL;
	NodeRandom* res1 = NULL;

	
	head = new NodeRandom(1);
	head->next = new NodeRandom(2);
	head->next->next = new NodeRandom(3);
	head->next->next->next = new NodeRandom(4);
	head->next->next->next->next = new NodeRandom(5);
	head->next->next->next->next->next = new NodeRandom(6);

	head->rand = head->next->next->next->next->next; // 1 -> 6
	head->next->rand = head->next->next->next->next->next; // 2 -> 6
	head->next->next->rand = head->next->next->next->next; // 3 -> 5
	head->next->next->next->rand = head->next->next; // 4 -> 3
	head->next->next->next->next->rand = NULL; // 5 -> null
	head->next->next->next->next->next->rand = head->next->next->next; // 6 -> 4


	printRandLinkedList(head);
	res1 = copyListWithRand(head);
	cout<<"*************"<<endl;
	printRandLinkedList(res1);
}
void CopyListWithRandom_main()
{
	cout<<"*****CopyListWithRandom_main********"<<endl;
	CopyListWithRandom_test();
	
}