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 integersa
andb
and returnsa + b
. Assume that if a value has already been cached for the arguments(b, a)
wherea != 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 integern
and returns1
ifn <= 1
orfib(n - 1) + fib(n - 2)
otherwise.
factorial accepts a single integern
and returns1
ifn <= 1
orfactorial(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 <= 105
> 1 <= n <= 10
> 0 <= actions.length <= 105
> actions.length === values.length
actions[i]
is one of "call" and "getCallCount"
fnName
is one of "sum", "factorial" and "fib"
Solution
As you continue to develop and optimize your JavaScript applications, remember the power of memoization. By identifying the right functions to memoize and implementing the appropriate caching strategies, you can unlock significant performance gains and create a more seamless and responsive user experience for your customers.
I hope this article helps. If you like the article, please leave a like and feel free to leave any concerns on the comment section. That is all for today.
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