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Commit c08e615

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committed
feat: add solutions to lcof2 problem: No.031
1 parent 113ee57 commit c08e615

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8 files changed

+983
-221
lines changed

8 files changed

+983
-221
lines changed

‎lcof2/剑指 Offer II 031. 最近最少使用缓存/README.md‎

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struct Node {
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int k;
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int v;
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Node* prev;
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Node* next;
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Node()
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: k(0)
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, v(0)
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, prev(nullptr)
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, next(nullptr) {}
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Node(int key, int val)
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: k(key)
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, v(val)
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, prev(nullptr)
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, next(nullptr) {}
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};
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class LRUCache {
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public:
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LRUCache(int capacity)
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: cap(capacity)
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, size(0) {
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head = new Node();
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tail = new Node();
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head->next = tail;
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tail->prev = head;
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}
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int get(int key) {
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if (!cache.count(key)) return -1;
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Node* node = cache[key];
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moveToHead(node);
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return node->v;
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}
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void put(int key, int value) {
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if (cache.count(key)) {
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Node* node = cache[key];
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node->v = value;
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moveToHead(node);
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} else {
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Node* node = new Node(key, value);
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cache[key] = node;
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addToHead(node);
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++size;
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if (size > cap) {
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node = removeTail();
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cache.erase(node->k);
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--size;
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}
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}
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}
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private:
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unordered_map<int, Node*> cache;
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Node* head;
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Node* tail;
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int cap;
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int size;
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void moveToHead(Node* node) {
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removeNode(node);
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addToHead(node);
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}
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void removeNode(Node* node) {
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node->prev->next = node->next;
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node->next->prev = node->prev;
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}
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void addToHead(Node* node) {
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node->next = head->next;
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node->prev = head;
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head->next = node;
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node->next->prev = node;
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}
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Node* removeTail() {
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Node* node = tail->prev;
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removeNode(node);
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return node;
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}
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};
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/**
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* Your LRUCache object will be instantiated and called as such:
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* LRUCache* obj = new LRUCache(capacity);
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* int param_1 = obj->get(key);
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* obj->put(key,value);
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*/
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public class LRUCache {
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class Node {
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public Node Prev;
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public Node Next;
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public int Key;
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public int Val;
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}
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private Node head = new Node();
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private Node tail = new Node();
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private Dictionary<int, Node> cache = new Dictionary<int, Node>();
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private readonly int capacity;
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private int size;
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public LRUCache(int capacity) {
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this.capacity = capacity;
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head.Next = tail;
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tail.Prev = head;
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}
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public int Get(int key) {
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Node node;
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if (cache.TryGetValue(key, out node)) {
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moveToHead(node);
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return node.Val;
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}
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return -1;
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}
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public void Put(int key, int Val) {
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Node node;
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if (cache.TryGetValue(key, out node)) {
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moveToHead(node);
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node.Val = Val;
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} else {
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node = new Node() { Key = key, Val = Val };
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cache.Add(key, node);
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addToHead(node);
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if (++size > capacity) {
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node = removeTail();
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cache.Remove(node.Key);
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--size;
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}
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}
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}
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private void moveToHead(Node node) {
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removeNode(node);
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addToHead(node);
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}
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private void removeNode(Node node) {
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node.Prev.Next = node.Next;
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node.Next.Prev = node.Prev;
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}
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private void addToHead(Node node) {
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node.Next = head.Next;
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node.Prev = head;
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head.Next = node;
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node.Next.Prev = node;
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}
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private Node removeTail() {
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Node node = tail.Prev;
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removeNode(node);
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return node;
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}
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}
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/**
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* Your LRUCache object will be instantiated and called as such:
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* LRUCache obj = new LRUCache(capacity);
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* int param_1 = obj.Get(key);
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* obj.Put(key,Val);
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*/
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type node struct {
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key, val int
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prev, next *node
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}
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type LRUCache struct {
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capacity int
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cache map[int]*node
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head, tail *node
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}
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func Constructor(capacity int) LRUCache {
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head := new(node)
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tail := new(node)
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head.next = tail
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tail.prev = head
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return LRUCache{
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capacity: capacity,
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cache: make(map[int]*node, capacity),
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head: head,
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tail: tail,
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}
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}
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func (this *LRUCache) Get(key int) int {
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n, ok := this.cache[key]
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if !ok {
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return -1
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}
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this.moveToFront(n)
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return n.val
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}
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func (this *LRUCache) Put(key int, value int) {
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n, ok := this.cache[key]
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if ok {
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n.val = value
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this.moveToFront(n)
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return
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}
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if len(this.cache) == this.capacity {
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back := this.tail.prev
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this.remove(back)
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delete(this.cache, back.key)
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}
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n = &node{key: key, val: value}
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this.pushFront(n)
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this.cache[key] = n
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}
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func (this *LRUCache) moveToFront(n *node) {
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this.remove(n)
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this.pushFront(n)
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}
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func (this *LRUCache) remove(n *node) {
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n.prev.next = n.next
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n.next.prev = n.prev
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n.prev = nil
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n.next = nil
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}
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func (this *LRUCache) pushFront(n *node) {
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n.prev = this.head
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n.next = this.head.next
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this.head.next.prev = n
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this.head.next = n
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}

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