[force buckle] copy the linked list with random pointer

138. Copy list with random pointer - Power button （LeetCode）

subject ：

Give you a length of n The linked list of , Each node contains an additional random pointer random , The pointer can point to any node or null node in the list .

To construct this linked list   Deep copy .  The deep copy should be made exactly by n individual new Node composition , The value of each new node is set to the value of its corresponding original node . New nodes next Pointers and random The pointer in the list should also point to the new node , And make these pointers in the original linked list and the copied linked list represent the same linked list state . The pointer in the copy linked list should not point to the node in the original linked list .

Ideas ：

Code ：

struct Node* copyRandomList(struct Node* head) 
{
	struct Node* cur = head;
    struct Node* copyHead = NULL;
    if(head == NULL)// The original linked list is empty 
    {
        return copyHead;
    }
    while(cur)
    {
        
        struct Node* copyNode = (struct Node*)malloc(sizeof(struct Node));
        copyNode->val = cur->val;
        copyNode->next = cur->next;
        cur->next = copyNode;
        cur = cur->next->next;
    }
    copyHead = head->next;
    cur = head;

    while(cur)
    {

        if(cur->random)
        {
            cur->next->random = cur->random->next;
        }
        else
        {
            cur->next->random = NULL;
        }
        cur = cur->next->next;
        
    }
    struct Node* temp = NULL;
    cur = copyHead;
    while(cur->next)
    {
        temp = cur->next->next;
        cur->next = temp;
        cur = temp;
    }
    return copyHead;
}