左神算法基础班3_13深度拷贝含有随机指针的链表

  1 #pragma once
  2 #include <iostream>
  3 #include <hash_map>
  4 
  5 using namespace std;
  6 
  7 struct Node
  8 {
  9     int val;
 10     Node *rand;
 11     Node *next;
 12     Node(int a = -1) :val(a), rand(NULL), next(NULL) {}
 13 };
 14 
 15 
 16 Node* CopeListDeep(Node* head)
 17 {
 18     hash_map<Node*, Node*>map;
 19     Node* p = head;
 20     while (p)//新建链表的结构
 21     {
 22         map[p] = new Node(-1);
 23         p = p->next;
 24     }
 25     
 26     p = head;
 27     while (p)//重构新链表的结构
 28     {
 29         map[p]->val = p->val;
 30         map[p]->next = map[p->next];
 31         map[p]->rand = map[p->rand];
 32         p = p->next;
 33     }
 34     return map[head];
 35 }
 36 
 37 Node* CopeListDeep2(Node* head)
 38 {
 39     Node* cur = head;
 40     Node* next = NULL;
 41     while (cur)//将原链表复制两份
 42     {
 43         next = cur->next;
 44         cur->next = new Node(cur->val);
 45         cur->next->next = next;//此处为复制两份的代码
 46         cur = next;
 47     }
 48 
 49     cur = head;    
 50     Node* copyHead = NULL;//为了区分原链
 51     //先复制rand节点
 52     while (cur)//将新建的节点的结构进行重构
 53     {
 54         next = cur->next->next;//原链表的遍历
 55         copyHead = cur->next;
 56         copyHead->rand = ((cur->rand) == NULL ? NULL : (cur->rand)->next);
 57         cur = next;
 58     }
 59     //copyHead已经是链表的末尾NULL
 60     cur = head;
 61     Node* res = head->next;
 62     while (cur)
 63     {
 64         next = cur->next->next;
 65         copyHead = cur->next;
 66         cur->next = next;
 67         copyHead->next = (next == NULL) ? NULL : next->next;
 68         cur = next;            
 69     }
 70 
 71     //为什么不一次性将原链表进行还原和复制链表进行重构？
 72     //因为一旦原链表前半部分还原，而后半部分一旦有rand指向前半部分，原链表是能找到所指向
 73     //的节点，但由于前半部分原链表已经还原了，所以复制链表的rand无法依据原链表的位置找到自己rand所指向的节点，
 74     //故得先将rand  copy出来。
 75     return res;    
 76 
 77 }
 78 
 79 
 80 void Test()
 81 {
 82     Node *head = new Node(-1);
 83     head->next = new Node(1);
 84     head->next->next = new Node(2);
 85     head->next->next->next = new Node(3);
 86     head->next->next->next->next = new Node(4);
 87     head->next->next->next->next->next = new Node(5);
 88     head->next->next->next->next->next->next = new Node(6);
 89     head->next->next->next->next->next->next->next = NULL;
 90 
 91 
 92     head->rand = NULL;
 93     head->next->rand = head->next->next->next->next->next->next;
 94     head->next->next->rand = head->next->next->next->next->next->next;
 95     head->next->next->next->rand = head->next->next->next->next->next;
 96     head->next->next->next->next->rand = head->next->next->next;
 97     head->next->next->next->next->next->rand = NULL;
 98     head->next->next->next->next->next->next->rand = head->next->next->next->next;
 99 
100 
101     cout << "打印原链表:" << endl;
102     Node*p = head->next;
103     while (p)
104     {
105         cout << "next: " << p->val << "   rand: " << ((p->rand) ? p->rand->val : -1) << endl;
106         p = p->next;
107     }
108 
109     cout << endl << "打印新链表:" << endl;
110     p = CopeListDeep2(head)->next;
111     while (p)
112     {
113         cout << "next: " << p->val << "   rand: " << ((p->rand) ? p->rand->val : -1) << endl;
114         p = p->next;
115     }
116 
117 
118 }