Add solution #2622

Author: JoshCrozier

README.md

@@ -365,6 +365,7 @@
 2619|[Array Prototype Last](./2619-array-prototype-last.js)|Easy|
 2620|[Counter](./2620-counter.js)|Easy|
 2621|[Sleep](./2621-sleep.js)|Easy|
+2622|[Cache With Time Limit](./2622-cache-with-time-limit.js)|Medium|
 2629|[Function Composition](./2629-function-composition.js)|Easy|
 3392|[Count Subarrays of Length Three With a Condition](./3392-count-subarrays-of-length-three-with-a-condition.js)|Easy|
 3396|[Minimum Number of Operations to Make Elements in Array Distinct](./3396-minimum-number-of-operations-to-make-elements-in-array-distinct.js)|Easy|

solutions/2622-cache-with-time-limit.js

@@ -0,0 +1,54 @@
+/**
+ * 2622. Cache With Time Limit
+ * https://leetcode.com/problems/cache-with-time-limit/
+ * Difficulty: Medium
+ *
+ * Write a class that allows getting and setting key-value pairs, however a time until
+ * expiration is associated with each key.
+ *
+ * The class has three public methods:
+ * - set(key, value, duration): accepts an integer key, an integer value, and a duration
+ *   in milliseconds. Once the duration has elapsed, the key should be inaccessible.
+ *   The method should return true if the same un-expired key already exists and false
+ *   otherwise. Both the value and duration should be overwritten if the key already exists.
+ *
+ * - get(key): if an un-expired key exists, it should return the associated value.
+ *   Otherwise it should return -1.
+ *
+ * - count(): returns the count of un-expired keys.
+ */
+
+var TimeLimitedCache = function() {
+  this.cache = new Map();
+};
+
+/**
+ * @param {number} key
+ * @param {number} value
+ * @param {number} duration time until expiration in ms
+ * @return {boolean} if un-expired key already existed
+ */
+TimeLimitedCache.prototype.set = function(key, value, duration) {
+  const hit = this.cache.has(key) && this.cache.get(key)[1] > Date.now();
+  this.cache.set(key, [value, Date.now() + duration]);
+  return hit;
+};
+
+/**
+ * @param {number} key
+ * @return {number} value associated with key
+ */
+TimeLimitedCache.prototype.get = function(key) {
+  if (!this.cache.has(key)) return -1;
+  const [value, expiredAt] = this.cache.get(key);
+  return expiredAt > Date.now() ? value : -1;
+};
+
+/**
+ * @return {number} count of non-expired keys
+ */
+TimeLimitedCache.prototype.count = function() {
+  return [...this.cache.keys()].reduce((count, key) => {
+    return this.cache.get(key)[1] > Date.now() ? ++count : count;
+  }, 0);
+};