Epoch-Based Reclamation Counter

Problem

Count reclaimed objects in an epoch-based reclamation scheme.

num_threads threads pin epochs; all start at epoch 0. Operations are "retire" (add an object at the current global epoch), "advance" (increment the global epoch), "pin" (values[i] is the thread that adopts the global epoch), and "reclaim" (free every retired object whose epoch is below the minimum pinned epoch and record how many were freed).

Return the list of freed counts.

Hint

Objects retire at the global epoch and are reclaimable once every pinned epoch has passed.

Test cases

case 1

in: [1,["retire","advance","pin","reclaim"],[0,0,0,0]]

expected: [1]

case 2

in: [1,["retire","reclaim"],[0,0]]

expected: [0]

case 3

in: [2,["retire","advance","pin","retire","advance","pin","reclaim"],[0,0,0,0,0,1,0]]

expected: [1]

case 4

in: [1,["retire","advance","advance","pin","reclaim","reclaim"],[0,0,0,0,0,0]]

expected: [1,0]

Starter codePython

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

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