LRU Cache LeetCode solution in C++

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class LRUCache {
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 public:
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  int mx;
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  class node {
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   public:
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    node *prev, *next;
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    int key, val;
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    node(int k, int v) {
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      key = k, val = v;
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    }
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  };
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  unordered_map<int, node *> mp;
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  node *head = new node(-1, -1);
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  node *tail = new node(-1, -1);
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  LRUCache(int capacity) {
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    mx = capacity;
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    mp.reserve(1024);
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    mp.max_load_factor(0.25);
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    head->next = tail;
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    tail->prev = head;
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  }
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  void addnode(node *temp) {
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    node *temp1 = head->next;
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    head->next = temp;
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    temp->prev = head;
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    temp->next = temp1;
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    temp1->prev = temp;
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  }
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  void deletenode(node *temp) {
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    node *temp1 = temp->prev;
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    node *temp2 = temp->next;
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    temp1->next = temp2;
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    temp2->prev = temp1;
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  }
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  int get(int key) {
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    if (mp.find(key) != mp.end()) {
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      node *temp = mp[key];
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      int res = temp->val;
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      mp.erase(key);
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      deletenode(temp);
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      addnode(temp);
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      mp[key] = head->next;
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      return res;
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    }
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    return -1;
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  }
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  void put(int key, int value) {
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    if (mp.find(key) != mp.end()) {
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      node *temp = mp[key];
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      mp.erase(key);
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      deletenode(temp);
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    }
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    if (mp.size() == mx) {
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      mp.erase(tail->prev->key);
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      deletenode(tail->prev);
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    }
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    addnode(new node(key, value));
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    mp[key] = head->next;
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  }
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};