Weak Reference Promotion

Problem

Simulate object lifetimes with strong references and weak reference checks.

operations contains "create" (register a new object with one strong reference), "ref" (add a strong reference when the object is alive), "release" (drop a strong reference and destroy the object at zero), "weak" (record whether a weak reference could be promoted, meaning the object is still alive), or "alive".

Return the list of recorded results (None for create, ref, and release).

Hint

A weak reference becomes invalid the moment the strong count reaches zero.

Test cases

case 1

in: [["create","weak","release","weak"],[1,1,1,1]]

expected: [null,true,null,false]

case 2

in: [["create","ref","release","alive"],[2,2,2,2]]

expected: [null,null,null,true]

case 3

in: [["weak"],[3]]

expected: [false]

case 4

in: [["create","create","release","alive"],[1,1,1,1]]

expected: [null,null,null,true]

Starter codePython

def weak_ref_sim(operations, values):
    # Your code here
    pass

4 test cases · run your code against them in the editor