Add solution #2623

Author: JoshCrozier

README.md

@@ -368,6 +368,7 @@
 2620|[Counter](./2620-counter.js)|Easy|
 2621|[Sleep](./2621-sleep.js)|Easy|
 2622|[Cache With Time Limit](./2622-cache-with-time-limit.js)|Medium|
+2623|[Memoize](./2623-memoize.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/2623-memoize.js

@@ -0,0 +1,41 @@
+/**
+ * 2623. Memoize
+ * https://leetcode.com/problems/memoize/
+ * Difficulty: Medium
+ *
+ * Given a function fn, return a memoized version of that function.
+ *
+ * A memoized function is a function that will never be called twice
+ * with the same inputs. Instead it will return a cached value.
+ *
+ * You can assume there are 3 possible input functions: sum, fib,
+ * and factorial.
+ *
+ * - `sum` accepts two integers a and b and returns a + b. Assume that
+ *   if a value has already been cached for the arguments (b, a) where
+ *   a != b, it cannot be used for the arguments (a, b). For example,
+ *   if the arguments are (3, 2) and (2, 3), two separate calls should
+ *   be made.
+ * - `fib` accepts a single integer n and returns 1 if n <= 1 or
+ *   fib(n - 1) + fib(n - 2) otherwise.
+ * - `factorial` accepts a single integer n and returns 1 if n <= 1 or
+ *   factorial(n - 1) * n otherwise.
+ */
+
+/**
+ * @param {Function} fn
+ * @return {Function}
+ */
+function memoize(fn) {
+  const cache = new Map();
+
+  return (...args) => {
+    const key = String(args);
+    if (cache.has(key)) {
+      return cache.get(key);
+    }
+    const value = fn(...args);
+    cache.set(key, value);
+    return value;
+  };
+}