2623. Memoize
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 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"
Solutions
Solution 1
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