Minimum Rounds to Complete All Tasks — LeetCode 2244 Python Solution

The problem

You are given a 0-indexed integer array tasks, where tasks[i] represents the difficulty level of a task. In each round, you can complete either 2 or 3 tasks of the same difficulty level.

Example

Input

tasks = [2,2,3,3,2,4,4,4,4,4]

Output

4

Explanation

To complete all the tasks, a possible plan is:

Python solution

class Solution:
    def minimumRounds(self, tasks: List[int]) -> int:
        cnt = Counter(tasks)
        ans = 0
        for v in cnt.values():
            if v == 1:
                return -1
            ans += v // 3 + (v % 3 != 0)
        return ans

Complexity

Pattern: Greedy

Take the locally best option every time — when you can prove that never costs you later. LeetCode 2244. Minimum Rounds to Complete All Tasks is filed here because LeetCode tags it Greedy, which is the vocabulary this hub collects.

The greedy guide has the Python template for the pattern and the 346 LeetCode problems that use it.

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