gistfile1.txt

/**
 * @param {number} capacity
 */
var LFUCache = function(capacity) {
  this.nodes = {};
  this.head = null;
  this.tail = null;
  this.size = 0;
  this.capacity = capacity;
};

/** 
* @param {number} key
* @return {number}
*/
LFUCache.prototype.get = function(key) {
  let node = this.nodes[key];
  if (node) {
    if (node.prev) {
      node.prev.next = node.next;
    }
    if (node.next) {
      node.next.prev = node.prev;
    }
    this.tail.next = node;
    node.prev = this.tail;
    node.next = null;
    this.tail = this.tail.next;
  }
  return node ? node.value : -1;
};

/** 
* @param {number} key 
* @param {number} value
* @return {void}
*/
LFUCache.prototype.put = function(key, value) {
  if (!this.nodes[value]) {
    this.size++;
    if (this.size === this.capacity) {
      console.log(this.head);
      this.head = this.head.next;
      this.head.prev = null;
      delete this.nodes[this.head.value];
    }
  }
  let node = new Node(value);
  if (!this.head) {
    this.head = this.tail = node;
  } else {
    this.tail.next = node;
    node.prev = this.tail;
    this.tail = this.tail.next;
  }
  this.nodes[value] = node;
};

class Node {
  constructor (value, next, prev) {
    this.value = value;
    this.next = next;
    this.prev = prev;
  }
}

/** 
* Your LFUCache object will be instantiated and called as such:
* var obj = Object.create(LFUCache).createNew(capacity)
* var param_1 = obj.get(key)
* obj.put(key,value)
*/


class TestSuite {
  constructor () {
    this.testsPassing = 0;
    this.testsFailing = 0;
  }

  expect (valOne, valTwo, testName) {
    if (JSON.stringify(valOne) === JSON.stringify(valTwo)) {
      this.testsPassing++;
    } else {
      this.testsFailing++;
      console.error(testName + ' - expected ' + valOne + ' to equal ' + valTwo);
    }
  }

  printReport () {
    console.log((this.testsPassing || 'No') + ' tests passing');
    console.log((this.testsFailing || 'No') + ' tests failing');
  }

  run () {
    let cache = new LFUCache(2);
    cache.put(1, 1);
    cache.put(2, 2);
    this.expect(cache.get(1), 1, 'test');
    cache.put(3, 3);
    this.expect(cache.get(2), -1, 'test');
    this.expect(cache.get(3), 3, 'test');
    cache.put(4, 4);
    this.expect(cache.get(1), -1, 'test');
    this.expect(cache.get(3), 3, 'test');
    this.expect(cache.get(4), 4, 'test');
    this.printReport();
  }
}

new TestSuite().run();