[LeetCode]Copy List with Random Pointer

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.

Return a deep copy of the list.

想了好久觉得这题不可能这么麻烦。看了答案。很巧。。赞。。。

http://fisherlei.blogspot.com/2013/11/leetcode-copy-list-with-random-pointer.html

/** * 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: RandomListNode *copyRandomList(RandomListNode *head) { if(head == NULL) return head; RandomListNode *tmp = head; while(tmp!= NULL) { RandomListNode *copytmp = new RandomListNode(tmp->label); copytmp->next = tmp->next; tmp->next = copytmp; tmp = copytmp->next; } tmp = head; while(tmp != NULL) { if(tmp->random != NULL) tmp->next->random = tmp->random->next; tmp = tmp->next->next; } tmp = head; RandomListNode *head2 = tmp->next; while(tmp != NULL) { RandomListNode *curr = tmp->next; tmp->next = curr->next; if(curr->next != NULL) curr->next = curr->next->next; tmp = tmp->next; } return head2; }};