How much work is still queued
Jobs arrive in batches and a single machine clears a fixed number per tick. Work that is not cleared this tick carries into the next.
- Each arrival adds its batch to the pending queue.
- Then the machine clears serviceRate of it — never more than what is pending.
- Each arrival is processed in sequence; return the queue left after the last tick.
- A service rate of zero or less clears nothing, so the sum of all arrivals is left.
queueAfter(arrivals: list<int>, serviceRate: int) → int
Java needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
int queueAfter(List<Integer> arrivals, int serviceRate) {
}Worked examples
| Call | Result |
|---|---|
queueAfter(Main.<Integer>ls(5, 3, 2), 4) | 0 |
queueAfter(Main.<Integer>ls(10, 0, 5), 4) | 3 |
queueAfter(Main.<Integer>ls(3, 3, 3), 1) | 6 |
queueAfter(Main.<Integer>ls(10, 10), 0) | 20 |
Hint
For each arrival add it, then subtract the smaller of the queue and the rate.
Reference solution in Java
int queueAfter(List<Integer> arrivals, int serviceRate) {
int pending = 0;
for (int a : arrivals) {
pending += a;
pending -= Math.min(pending, serviceRate);
}
return pending;
}