WhenAll Total Time

await Task.WhenAll(tasks) starts a group of tasks together and continues when the slowest one finishes. A program that awaits several groups one after another therefore takes the sum of the slowest task of each group.

Implement when_all_total_time(groups), where groups[i] lists the durations of the tasks in group i.

Input

groups: The groups, awaited in order. An empty group finishes immediately.

Output

Return the total time.

Restricciones

0 ≤ number of groups ≤ 10,000

0 ≤ tasks per group ≤ 1,000; 0 ≤ duration ≤ 10^6

Ejemplos

Entrada:
groups = [
    [3, 1, 2],
    [5],
    [2, 2]
]

Salida esperada:
expected = 10

Entrada:
std::vector<std::vector<long long>> groups = {
    {3, 1, 2},
    {5},
    {2, 2}
};

Salida esperada:
long long expected = 10;

Entrada:
long[][] groups = new long[][] {
    new long[] {3, 1, 2},
    new long[] {5},
    new long[] {2, 2}
};

Salida esperada:
long expected = 10;

Entrada:
groups = [
    [],
    [4, 7]
]

Salida esperada:
expected = 7

Entrada:
std::vector<std::vector<long long>> groups = {
    {},
    {4, 7}
};

Salida esperada:
long long expected = 7;

Entrada:
long[][] groups = new long[][] {
    new long[] {},
    new long[] {4, 7}
};

Salida esperada:
long expected = 7;

Referencias

Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.

• Microsoft Learn, Asynchronous programming with async and await