O(1)时间复杂度删除链表节点/复制带随机指针的链表

在O(1)时间复杂度删除链表节点

class Solution {
public:
/**
* @param node: a node in the list should be deleted
* @return: nothing
*/
void deleteNode(ListNode *node) {
// write your code here
if(node==NULL)
return;

ListNode* cur=node->next;
node->val=cur->val;
node->next=cur->next;
delete cur;

}
};

复制带随机指针的链表

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
if(head==NULL)
return head;
unordered_map<RandomListNode*, RandomListNode*> hashmap;
RandomListNode* cur=head;
while (cur != NULL)
{
hashmap.insert(make_pair(cur, new RandomListNode(cur->label)));
cur = cur->next;
}
cur=head;
for (; cur != NULL; cur=cur->next)
{
hashmap[cur]->next = hashmap[cur->next];
hashmap[cur]->random = hashmap[cur->random];
}
return hashmap[head];
}
};