JZ35 replication of complex linked list

Topic link ： Replication of complex linked list _ Niuke Tiba _ Cattle from

Be careful ：

It mainly considers the corresponding relationship between old and new nodes , as well as random Empty or pointing to your own situation

/*
struct RandomListNode {
    int label;
    struct RandomListNode *next, *random;
    RandomListNode(int x) :
            label(x), next(NULL), random(NULL) {
    }
};
*/
class Solution {
public:
    RandomListNode* Clone(RandomListNode* pHead) {
    if(!pHead) return NULL;
    // Define the head pointer of the new linked list 
    RandomListNode* newhead = new RandomListNode(pHead->label);
    //po Point to the header of the old linked list ,pn Point to the head of the new list 
    RandomListNode* po = pHead, *pn = newhead;
    // Hash is used to record whether the new node corresponding to the old node has been opened , And store the addresses of the old linked list and the first linked list 
    unordered_map<RandomListNode*, RandomListNode*> map;
    // First traversal . Save the old and new mapping relationship of each node 
    while(po){
        map[po] = new RandomListNode(po->label);
        po = po->next;
    }
    po = pHead;
    // The second traversal gives each node random and next Member assignment 
    while(po){
        pn->next = map[po->next];
        pn->random = map[po->random];
        po = po->next;
        pn = pn->next;
    }
        return newhead;
    }
};