Write-Through vs Write-Back Policy Simulation

Problem

Count the memory writes performed under two cache policies.

policy is either "through" or "back". operations contains "write" (dirty the block in addresses[i]) or "flush" (write all dirty blocks to memory and clear them). A write-through cache writes to memory on every write, while a write-back cache writes only on flush.

Return the total number of memory writes.

Hint

A set of dirty block addresses is enough; repeating a write to the same block stays one dirty block.

Test cases

case 1

in: ["through",["write","write","flush"],[1,2,0]]

expected: 2

case 2

in: ["back",["write","write","flush"],[1,2,0]]

expected: 2

case 3

in: ["back",["write","write","write"],[1,1,2]]

expected: 0

case 4

in: ["back",["write","flush","write","flush"],[1,0,1,0]]

expected: 2

case 5

in: ["through",["flush"],[0]]

expected: 0

Starter codePython

def memory_write_count(policy, operations, addresses):
    # Your code here
    pass

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