LintCode-105.复制带随机指针的链表

复制带随机指针的链表

code

/**
* Definition for singly-linked list with a random pointer.
* struct RandomListNode {
*     int label;
*     RandomListNode *next, *random;
*     RandomListNode(int x) : label(x), next(NULL), random(NULL) {}
* };
*/
class Solution {
public:
/**
* @param head: The head of linked list with a random pointer.
* @return: A new head of a deep copy of the list.
*/

RandomListNode *copyRandomList(RandomListNode *head) {
// write your code here
RandomListNode * newHead;
map<RandomListNode *, RandomListNode *> mapRandom;

newHead = createListNext(head, mapRandom);
newHead = createListRandom(head, newHead, mapRandom);

return newHead;
}

RandomListNode *createListNext(RandomListNode *head, map<RandomListNode *, RandomListNode *> &mapRandom) {
// write your code here
RandomListNode * newHead;
RandomListNode * p=head, *q;

if(head == NULL)
return NULL;

q = newHead = new RandomListNode(p->label);
mapRandom.insert(pair<RandomListNode *, RandomListNode *>(p, q));
p = p->next;

while(p != NULL) {
q->next = new RandomListNode(p->label);
mapRandom.insert(pair<RandomListNode *, RandomListNode *>(p, q->next));
q = q->next;
p = p->next;
}

return newHead;
}
RandomListNode *createListRandom(RandomListNode *head,RandomListNode *newHead, map<RandomListNode *, RandomListNode *> &mapRandom) {
// write your code here
RandomListNode * p=head;
RandomListNode * q=newHead;

if(head == NULL)
return NULL;

while(p != NULL) {
if(p->random != NULL) {
map<RandomListNode *, RandomListNode *>::iterator it = mapRandom.find(p->random);
q->random = it->second;
}
p = p->next;
q = q->next;
}

return newHead;
}
};