code added

Author: Bharat2044

11_memoize.js

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+// Question Link: https://leetcode.com/problems/memoize/?envType=study-plan-v2&envId=30-days-of-javascript
+// Solution Link: https://leetcode.com/problems/memoize/solutions/5435256/2-javascript-easy-solution/
+
+/*
+2623. Memoize
+
+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.
+ 
+Example 1:
+Input:
+fnName = "sum"
+actions = ["call","call","getCallCount","call","getCallCount"]
+values = [[2,2],[2,2],[],[1,2],[]]
+Output: [4,4,1,3,2]
+Explanation:
+const sum = (a, b) => a + b;
+const memoizedSum = memoize(sum);
+memoizedSum(2, 2); // "call" - returns 4. sum() was called as (2, 2) was not seen before.
+memoizedSum(2, 2); // "call" - returns 4. However sum() was not called because the same inputs were seen before.
+// "getCallCount" - total call count: 1
+memoizedSum(1, 2); // "call" - returns 3. sum() was called as (1, 2) was not seen before.
+// "getCallCount" - total call count: 2
+
+Example 2:
+Input:
+fnName = "factorial"
+actions = ["call","call","call","getCallCount","call","getCallCount"]
+values = [[2],[3],[2],[],[3],[]]
+Output: [2,6,2,2,6,2]
+Explanation:
+const factorial = (n) => (n <= 1) ? 1 : (n * factorial(n - 1));
+const memoFactorial = memoize(factorial);
+memoFactorial(2); // "call" - returns 2.
+memoFactorial(3); // "call" - returns 6.
+memoFactorial(2); // "call" - returns 2. However factorial was not called because 2 was seen before.
+// "getCallCount" - total call count: 2
+memoFactorial(3); // "call" - returns 6. However factorial was not called because 3 was seen before.
+// "getCallCount" - total call count: 2
+
+Example 3:
+Input:
+fnName = "fib"
+actions = ["call","getCallCount"]
+values = [[5],[]]
+Output: [8,1]
+Explanation:
+fib(5) = 8 // "call"
+// "getCallCount" - total call count: 1
+ 
+Constraints:
+0 <= a, b <= 10^5
+1 <= n <= 10
+0 <= actions.length <= 10^5
+actions.length === values.length
+actions[i] is one of "call" and "getCallCount"
+fnName is one of "sum", "factorial" and "fib"
+*/
+
+
+/**
+ * @param {Function} fn
+ * @return {Function}
+ */
+function memoize(fn) {
+
+    const cache = {};
+    
+    return function(...args) {
+        const key = args;
+
+        if (key in cache) {
+            return cache[key];
+        }
+
+        const output = fn(...args);
+        cache[key] = output;
+
+        return output;        
+    }
+}
+
+
+/** 
+ * let callCount = 0;
+ * const memoizedFn = memoize(function (a, b) {
+ *	 callCount += 1;
+ *   return a + b;
+ * })
+ * memoizedFn(2, 3) // 5
+ * memoizedFn(2, 3) // 5
+ * console.log(callCount) // 1 
+ */