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
SOLUTION:
from collections import Counter
class Solution:
def minimumRounds(self, tasks: List[int]) -> int:
rounds = 0
ctr = Counter(tasks)
for f in ctr.values():
found = False
for i in range(f // 3, -1, -1):
if (f - 3 * i) % 2 == 0:
rounds += i + (f - 3 * i) // 2
found = True
break
if not found:
return -1
return rounds
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