"content":"<p>Given a function <code>fn</code>, return a <strong>memoized</strong> version of that function.</p>\n\n<p>A <strong>memoized </strong>function is a function that will never be called twice with the same inputs. Instead it will return a cached value.</p>\n\n<p>You can assume there are <strong>3 </strong>possible input functions: <code>sum</code><strong>, </strong><code>fib</code><strong>, </strong>and <code>factorial</code><strong>.</strong></p>\n\n<ul>\n\t<li><code>sum</code><strong> </strong>accepts two integers <code>a</code> and <code>b</code> and returns <code>a + b</code>.</li>\n\t<li><code>fib</code><strong> </strong>accepts a single integer <code>n</code> and returns <code>1</code> if <font face=\"monospace\"><code>n <= 1</code> </font>or<font face=\"monospace\"> <code>fib(n - 1) + fib(n - 2)</code> </font>otherwise.</li>\n\t<li><code>factorial</code> accepts a single integer <code>n</code> and returns <code>1</code> if <code>n <= 1</code> or <code>factorial(n - 1) * n</code> otherwise.</li>\n</ul>\n\n<p> </p>\n<p><strong class=\"example\">Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong>\nfnName = "sum"\nactions = ["call","call","getCallCount","call","getCallCount"]\nvalues = [[2,2],[2,2],[],[1,2],[]]\n<strong>Output:</strong> [4,4,1,3,2]\n<strong>Explanation:</strong>\nconst sum = (a, b) => a + b;\nconst memoizedSum = memoize(sum);\nmemoizedSum(2, 2); // "call" - returns 4. sum() was called as (2, 2) was not seen before.\nmemoizedSum(2, 2); // "call" - returns 4. However sum() was not called because the same inputs were seen before.\n// "getCallCount" - total call count: 1\nmemoizedSum(1, 2); // "call" - returns 3. sum() was called as (1, 2) was not seen before.\n// "getCallCount" - total call count: 2\n</pre>\n\n<p><strong class=\"example\">Example 2:</strong></p>\n\n<pre>\n<strong>Input:\n</strong>fnName = "factorial"\nactions = ["call","call","call","getCallCount","call","getCallCount"]\nvalues = [[2],[3],[2],[],[3],[]]\n<strong>Output:</strong> [2,6,2,2,6,2]\n<strong>Explanation:</strong>\nconst factorial = (n) => (n <= 1) ? 1 : (n * factorial(n - 1));\nconst memoFactorial = memoize(factorial);\nmemoFactorial(2); // "call" - returns 2.\nmemoFactorial(3); // "call" - returns 6.\nmemoFactorial(2); // "call" - returns 2. However factorial was not called because 2 was seen before.\n// "getCallCount" - total call count: 2\nmemoFactorial(3); // "call" - returns 6. However factorial was not called because 3 was seen before.\n// "getCallCount" - total call count: 2\n</pre>\n\n<p><strong class=\"example\">Example 3:</strong></p>\n\n<pre>\n<strong>Input:\n</strong>fnName = "fib"\nactions = ["call","getCallCount"]\nvalues = [[5],[]]\n<strong>Output:</strong> [8,1]\n<strong>Explanation:\n</strong>fib(5) = 8 // "call"\n// "getCallCount" - total call count: 1\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>0 <= a, b <= 10<sup>5</sup></code></li>\n\t<li><code>1 <= n <= 10</code></li>\n\t<li><code>0 <= actions.length <= 10<sup>5</sup></code></li>\n\t<li><code>actions.length === values.length</code></li>\n\t<li><code>actions[i]</code> is one of "call" and "getCallCount"</li>\n\t<li><code>fnName</code> is one of "sum", "factorial" and "fib"</li>\n</ul>\n",
"You can create copy of a function by spreading function parameters. \r\n\r\nfunction outerFunction(passedFunction) {\r\n return newFunction(...params) {\r\n return passedFunction(...params);\r\n };\r\n}",
"params is an array. Since you know all values in the array are numbers, you can turn it into a string with JSON.stringify().",
"In the outerFunction, you can declare a Map or Object. In the inner function you can avoid executing the passed function if the params have already been passed before."
