Условие
With async/await you can start several tasks and let them run at the same time. A SemaphoreSlim often caps how many run at once.
Tasks numbered 0 to n − 1 take durations[i] time units. At time 0 start as many tasks as the limit allows, in index order. Whenever tasks finish, record them (if several finish at the same moment, lower index first) and immediately start the next waiting tasks, in index order, to fill the free slots.
Implement parallel_task_order(durations, limit).
Input
durations: How long each task takes.
limit: The maximum number of tasks running at the same time.
Output
Return the task indices in the order they finish.
Ограничения
1 ≤ n ≤ 100,000
1 ≤ durations[i] ≤ 10^6; 1 ≤ limit ≤ n
Примеры
Ввод:
limit = 2
durations = [4, 2, 3, 1]
Ожидаемый вывод:
expected = [1, 0, 2, 3]
Ввод:
long long limit = 2;
std::vector<long long> durations = {4, 2, 3, 1};
Ожидаемый вывод:
std::vector<long long> expected = {1, 0, 2, 3};
Ввод:
long limit = 2;
long[] durations = new long[] {4, 2, 3, 1};
Ожидаемый вывод:
long[] expected = new long[] {1, 0, 2, 3};
Пояснение
Tasks 0 and 1 start. Task 1 ends at 2 and task 2 starts (ends at 5). Task 0 ends at 4 and task 3 starts (ends at 5). Tasks 2 and 3 finish together, lower index first: [1, 0, 2, 3].
Ввод:
limit = 3
durations = [3, 1, 2]
Ожидаемый вывод:
expected = [1, 2, 0]
Ввод:
long long limit = 3;
std::vector<long long> durations = {3, 1, 2};
Ожидаемый вывод:
std::vector<long long> expected = {1, 2, 0};
Ввод:
long limit = 3;
long[] durations = new long[] {3, 1, 2};
Ожидаемый вывод:
long[] expected = new long[] {1, 2, 0};
Пояснение
All tasks run at once and finish at 1, 2 and 3: [1, 2, 0].
Как подступиться
Сначала попробуйте сами, затем открывайте подсказки по одной.
Подсказка 1
Keep the running tasks ordered by finish time, then by index.
Подсказка 2
Each step jumps to the next finish time and collects every task ending then.
Подсказка 3
Refill free slots with the next waiting tasks in index order.
Ожидаемая сложность
O(n log limit) time, O(limit) extra space
Ссылки
Это задание адаптировано для CodeUtility. Следуйте условию и ограничениям выше.