Add solution #2630

Author: JoshCrozier

README.md

@@ -370,6 +370,7 @@
 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|
+2630|[Memoize II](./2630-memoize-ii.js)|Hard|
 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|
 3397|[Maximum Number of Distinct Elements After Operations](./3397-maximum-number-of-distinct-elements-after-operations.js)|Medium|

solutions/2630-memoize-ii.js

@@ -0,0 +1,30 @@
+/**
+ * 2630. Memoize II
+ * https://leetcode.com/problems/memoize-ii/
+ * Difficulty: Hard
+ *
+ * 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.
+ *
+ * fn can be any function and there are no constraints on what type
+ * of values it accepts. Inputs are considered identical if they
+ * are === to each other.
+ */
+
+/**
+ * @param {Function} fn
+ * @return {Function}
+ */
+function memoize(fn) {
+  const cache = {};
+  const idLookup = new Map();
+  function generateId(item) {
+    return idLookup.get(item) ?? idLookup.set(item, idLookup.size + 1).get(item);
+  }
+  return (...args) => {
+    const key = args.map(generateId).join('-');
+    return !cache.hasOwnProperty(key) ? (cache[key] = fn(...args)) : cache[key];
+  };
+}