# 2244 Minimum Rounds to Complete All Tasks

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.

Return the minimum rounds required to complete all the tasks, or `-1` if it is not possible to complete all the tasks.

Example 1:

``````Input: tasks = [2,2,3,3,2,4,4,4,4,4]
Output: 4
Explanation: To complete all the tasks, a possible plan is:
- In the first round, you complete 3 tasks of difficulty level 2.
- In the second round, you complete 2 tasks of difficulty level 3.
- In the third round, you complete 3 tasks of difficulty level 4.
- In the fourth round, you complete 2 tasks of difficulty level 4.
It can be shown that all the tasks cannot be completed in fewer than 4 rounds, so the answer is 4.
``````

Example 2:

``````Input: tasks = [2,3,3]
Output: -1
Explanation: There is only 1 task of difficulty level 2, but in each round,
you can only complete either 2 or 3 tasks of the same difficulty level.
Hence, you cannot complete all the tasks, and the answer is -1.
``````

Constraints:

• `1 <= tasks.length <= 105`
• `1 <= tasks[i] <= 109`
 `````` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 `````` ``````class Solution: def minimumRounds(self, tasks: List[int]) -> int: count = defaultdict(int) for t in tasks: count[t] += 1 res = 0 for v in count.values(): if v < 2: return -1 res += v // 3 if v % 3: res += 1 return res ''' Short version ''' class Solution: def minimumRounds(self, tasks): freq = Counter(tasks).values() return -1 if 1 in freq else sum((a + 2) // 3 for a in freq)``````