138.复制带随机指针的链表

🥶map

class Solution {
public:
    Node* copyRandomList(Node* head) {
        Node* new_prev = new Node(0);
        new_prev->next = helper(head);
        return new_prev->next;
    }
    Node* helper(Node* nd) {
        if(!nd)
            return nullptr;
        if(mp.count(nd))
            return mp[nd];
        Node* neo = new Node(nd->val);
        mp[nd] = neo;
        neo->next = helper(nd->next);
        neo->random = helper(nd->random);
        return neo;
    }
private:
    map<Node*, Node*> mp;
};

Accepted

18/18 cases passed (20 ms)

Your runtime beats 44.06 % of cpp submissions

Your memory usage beats 69.77 % of cpp submissions (15 MB)