/**
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* A simple LRU cache implementation
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* @param K - Key type
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* @param V - Value type
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* @example
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* const cache = new LRUCache<string, number>(10);
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* cache.set("foo", 1);
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* cache.set("bar", 2);
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* cache.set("baz", 3);
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* cache.set("qux", 4);
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*/
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export class LRUCache<K, V> {
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private maxSize: number;
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private map: Map<K, V>;
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constructor(maxSize: number) {
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this.maxSize = maxSize;
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this.map = new Map();
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}
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get(key: K): V | undefined {
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if (!this.map.has(key)) return undefined;
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// Touch: move to end (most recently used)
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const value = this.map.get(key)!;
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this.map.delete(key);
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this.map.set(key, value);
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return value;
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}
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set(key: K, value: V): void {
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if (this.map.has(key)) {
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this.map.delete(key);
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} else if (this.map.size >= this.maxSize) {
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// Remove least recently used (first item)
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const lru = this.map.keys().next();
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if (!lru.done) {
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this.map.delete(lru.value);
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}
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}
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this.map.set(key, value);
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}
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has(key: K): boolean {
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return this.map.has(key);
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}
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get size(): number {
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return this.map.size;
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}
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values(): IterableIterator<V> {
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return this.map.values();
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}
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}
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