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.

Contraintes

0 ≤ number of groups ≤ 10,000

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

Exemples

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

Sortie attendue :
expected = 10

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

Sortie attendue :
long long expected = 10;

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

Sortie attendue :
long expected = 10;

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

Sortie attendue :
expected = 7

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

Sortie attendue :
long long expected = 7;

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

Sortie attendue :
long expected = 7;

Références

Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.

• Microsoft Learn, Asynchronous programming with async and await