Pick the next server in round-robin
A load balancer cycles through servers by index. Given the current slot and the total count, return the next one.
- The next server is (current + 1) modulo servers.
- When servers is zero or negative, return 0.
RoundRobinNext(current: int, servers: int) → int
C# 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
public int RoundRobinNext(int current, int servers) {
}Worked examples
| Call | Result |
|---|---|
RoundRobinNext(0, 5) | 1 |
RoundRobinNext(4, 5) | 0 |
RoundRobinNext(0, 1) | 0 |
RoundRobinNext(3, 0) | 0 |
Hint
Modulo wraps the index back to zero.
Reference solution in C#
public int RoundRobinNext(int current, int servers) {
if (servers <= 0) return 0;
return (((current + 1) % servers) + servers) % servers;
}