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Task Scheduler

Detailed guide and Python implementation for the 'Task Scheduler' problem.

Problem Statement

Easy

You are given an array of CPU tasks, each represented by a letter A to Z, and a cooling interval n. Each cycle or interval allows the completion of one task. Tasks can be completed in any order, but there's a constraint: identical tasks must be separated by at least n intervals due to cooling requirements.

Return the minimum number of intervals required to complete all tasks.

Write a function leastInterval(tasks: List[str], n: int) -> int.

Constraints
  • 1 <= len(tasks) <= 10^4
  • tasks[i] is an uppercase English letter
  • 0 <= n <= 100

Examples

Example 1
Input
tasks = ["A","A","A","B","B","B"], n = 2
Output
8
Explanation

A possible sequence is A -> B -> idle -> A -> B -> idle -> A -> B.

Example 2
Input
tasks = ["A","A","A","B","B","B"], n = 0
Output
6
Explanation

With no cooling interval, tasks can be executed continuously without idles.

Need a Hint?
Consider using Heap / Priority Queue-specific data structures like sets or heaps.
Edge Cases to Watch
  • Empty input structures
  • Single element inputs
  • Large numerical bounds

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