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Consider a CPU task scheduler where tasks are represented by characters and each task requires 1 unit of time. If the cooldown period n is 2, what is the minimum time to complete tasks ['B','B','A']?

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Greedy Algorithms - Task Scheduler (CPU Cooling)

Consider a CPU task scheduler where tasks are represented by characters and each task requires 1 unit of time. If the cooldown period n is 2, what is the minimum time to complete tasks ['B','B','A']?

A3

B5

C6

D4

Step-by-Step Solution

Solution:

Step 1: Count task frequencies
Tasks: B=2, A=1
Step 2: Calculate max frequency and idle slots
Max frequency = 2 (for B), idle slots = (2-1)*2 = 2
Step 3: Fill idle slots with other tasks
One A fills one idle slot, remaining idle = 1
Step 4: Total time = tasks + idle slots
Total time = 3 (tasks) + 1 (idle) = 4
Final Answer:
Option D -> Option D
Quick Check:
Schedule: B -> A -> idle -> B [OK]

Quick Trick: Calculate idle slots from max frequency tasks [OK]

Common Mistakes:

MISTAKES

Ignoring idle time between tasks
Assuming tasks can be scheduled back-to-back without cooldown

Trap Explanation:

PITFALL

Choosing total tasks count without accounting for cooldown idle time

Interviewer Note:

CONTEXT

Tests understanding of cooldown and idle slot calculation

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