[Solved] A developer wrote this pseudocode for two threads incrementing a shared counter: Thread 1: lock.acquire() counter += 1 lock.release() Thread 2: lock.acquire() counter += 1 lock.... | LLD

LLD - Design — Parking Lot System

A developer wrote this pseudocode for two threads incrementing a shared counter:

Thread 1:
lock.acquire()
counter += 1
lock.release()

Thread 2:
lock.acquire()
counter += 1
lock.release()

But the counter sometimes ends up incorrect. What is the likely mistake?

AUsing the same lock object for both threads

BNot acquiring the lock before incrementing

CReleasing the lock before incrementing

DLock object is not shared between threads

Step-by-Step Solution

Solution:

Step 1: Analyze lock usage
Both threads acquire and release a lock around increment, which is correct if the lock is shared.
Step 2: Identify cause of incorrect counter
If the lock object is not shared, each thread locks independently, causing race conditions.
Final Answer:
Lock object is not shared between threads -> Option D
Quick Check:
Shared lock needed for correct synchronization [OK]

Quick Trick: Ensure lock object is shared among threads [OK]

Common Mistakes:

MISTAKES

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