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* fix #844 * formatted code according to standard.js
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@ -1,88 +1,39 @@
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class DoubleLinkedListNode {
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// Double Linked List Node built specifically for LRU Cache
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constructor (key, val) {
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this.key = key
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this.val = val
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this.next = null
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this.prev = null
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}
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}
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class DoubleLinkedList {
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// Double Linked List built specifically for LRU Cache
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constructor () {
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this.head = new DoubleLinkedListNode(null, null)
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this.rear = new DoubleLinkedListNode(null, null)
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this.head.next = this.rear
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this.rear.prev = this.head
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}
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add (node) {
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// Adds the given node to the end of the list (before rear)
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const temp = this.rear.prev
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temp.next = node
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node.prev = temp
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this.rear.prev = node
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node.next = this.rear
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}
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remove (node) {
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// Removes and returns the given node from the list
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const tempLast = node.prev
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const tempNext = node.next
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node.prev = null
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node.next = null
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tempLast.next = tempNext
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tempNext.prev = tempLast
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return node
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}
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}
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class LRUCache {
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// LRU Cache to store a given capacity of data
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constructor (capacity) {
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this.list = new DoubleLinkedList()
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this.cache = new Map()
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this.capacity = capacity
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this.numKeys = 0
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this.hits = 0
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this.miss = 0
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this.cache = {}
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}
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cacheInfo () {
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// Return the details for the cache instance [hits, misses, capacity, current_size]
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return `CacheInfo(hits=${this.hits}, misses=${this.miss}, capacity=${this.capacity}, current size=${this.numKeys})`
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return `CacheInfo(hits=${this.hits}, misses=${this.miss}, capacity=${this.capacity}, current size=${this.cache.size})`
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}
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set (key, value) {
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// Sets the value for the input key and updates the Double Linked List
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if (!(key in this.cache)) {
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if (this.numKeys >= this.capacity) {
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const keyToDelete = this.list.head.next.key
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this.list.remove(this.cache[keyToDelete])
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delete this.cache[keyToDelete]
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this.numKeys -= 1
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}
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this.cache[key] = new DoubleLinkedListNode(key, value)
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this.list.add(this.cache[key])
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this.numKeys += 1
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} else {
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const node = this.list.remove(this.cache[key])
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node.val = value
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this.list.add(node)
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// Sets the value for the input key and if the key exists it updates the existing key
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if (this.cache.size === this.capacity) {
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// delete oldest key existing in map
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this.cache.delete(this.cache.keys().next().value)
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}
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this.cache.set(key, value)
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}
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get (key) {
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// Returns the value for the input key and updates the Double Linked List. Returns null if key is not present in cache
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if (key in this.cache) {
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// Returns the value for the input key. Returns null if key is not present in cache
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if (this.cache.has(key)) {
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const value = this.cache.get(key)
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// refresh the cache to update the order of key
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this.cache.delete(key)
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this.cache.set(key, value)
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this.hits += 1
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this.list.add(this.list.remove(this.cache[key]))
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return this.cache[key].val
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return value
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} else {
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this.miss += 1
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return null
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}
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this.miss += 1
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return null
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}
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}
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