44. LRU Cache Implementation

class LRU {
  constructor(cap) { this.cap = cap; this.cache = new Map(); }
  get(k) {
    if (!this.cache.has(k)) return null;
    const v = this.cache.get(k);
    this.cache.delete(k); this.cache.set(k, v);
    return v;
  }
  put(k, v) {
    if (this.cache.has(k)) this.cache.delete(k);
    this.cache.set(k, v);
    if (this.cache.size > this.cap) this.cache.delete(this.cache.keys().next().value);
  }
}