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#2623 - Memoize
Problem Description
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.
Solution
/**
* @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;
};
}