剑指offer 复杂链表的复制

1 struct RandomListNode {
2     int label;
3     struct RandomListNode *next, *random;
4     RandomListNode(int x) :
5             label(x), next(NULL), random(NULL) {
6     }
7 };

 1 /*
 2 struct RandomListNode {
 3     int label;
 4     struct RandomListNode *next, *random;
 5     RandomListNode(int x) :
 6             label(x), next(NULL), random(NULL) {
 7     }
 8 };
 9 */
10 class Solution {
11 public:
12     RandomListNode* Clone(RandomListNode* pHead)
13     {
14         RandomListNode *res = new RandomListNode(0), *tmp = res, *pNode = pHead; //res是一个没有用的头结点。
15         map<RandomListNode*, RandomListNode*> mp;
16         while (pNode != NULL) {
17             RandomListNode *node = new RandomListNode(pNode->label); //创建新节点N‘(node)
18             tmp->next = node;
19             tmp = node;
20             mp[pNode] = node; //建立哈希映射<N, N‘>
21             pNode = pNode->next;
22         }
23         tmp = pHead;
24         for (map<RandomListNode*, RandomListNode*>::iterator it = mp.begin(); it != mp.end(); it++) {
25             //it->second: N‘, it->first: N, if->first->random: S, mp[S] = S‘
26             it->second->random = mp[it->first->random]; 
27         }
28         return res->next;
29     }
30 };

 1 /*
 2 struct RandomListNode {
 3     int label;
 4     struct RandomListNode *next, *random;
 5     RandomListNode(int x) :
 6             label(x), next(NULL), random(NULL) {
 7     }
 8 };
 9 */
10 class Solution {
11 public:
12     RandomListNode* Clone(RandomListNode* pHead)
13     {
14         if (pHead == NULL)
15             return NULL;
16         RandomListNode *pCurrent = pHead, *copyCurrent = NULL;
17         //复制一遍链表
18         while (pCurrent != NULL) {
19             RandomListNode* node = new RandomListNode(pCurrent->label);
20             node->next = pCurrent->next;
21             pCurrent->next = node;
22             pCurrent = node->next;
23         }
24         
25         pCurrent = pHead;
26         while (pCurrent != NULL) {
27             copyCurrent = pCurrent->next;
28             if (pCurrent->random != NULL)
29                 copyCurrent->random = pCurrent->random->next;
30             pCurrent = copyCurrent->next;
31         }
32         RandomListNode* pNode = pHead;
33         RandomListNode* pClonedHead = pNode->next;
34         RandomListNode* pClonedNode = pNode->next;
35 
36         pNode->next = pClonedNode->next;
37         pNode = pClonedNode->next;
38         while (pNode != NULL) {
39             pClonedNode->next = pNode->next;
40             pClonedNode = pNode->next;
41             pNode->next = pClonedNode->next;
42             pNode = pClonedNode->next;
43         }
44         return pClonedHead;
45     }
46 };