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ElevatorAlgorithm.java
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61 lines (45 loc) · 1.79 KB
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import java.util.Arrays;
import java.util.Collections;
import java.util.List;
public class ElevatorAlgorithm {
static void startCSCAN(int pos, List<Integer> disk_requests)
{
System.out.println("Using C-SCAN algorithm on pending dist requests: " + disk_requests);
System.out.println("Starting position is: " + pos + "\n");
if (disk_requests.size() == 0)
{
System.out.println("Nothing to do.");
}
Collections.sort(disk_requests);
int next_array_pos = disk_requests.stream()
.map(disk_requests::indexOf)
.filter(x -> disk_requests.get(x) > pos)
.findFirst().orElse(0);
int curr_position = pos;
int seek_number = 1;
int motion_sum = 0;
for (int i = 0; i < disk_requests.size(); i++)
{
if (next_array_pos == 0 && curr_position != 0)
{
curr_position = 0;
System.out.println("Seek " + seek_number + ": returning head to track 0, motion: 0");
seek_number++;
}
int next_position = disk_requests.get(next_array_pos);
int motion = Math.abs(curr_position-next_position);
System.out.println("Seek " + seek_number + ": " + next_position + "-" + curr_position + " motion: " + motion);
seek_number++;
motion_sum += motion;
curr_position = next_position;
next_array_pos = (next_array_pos+1)%disk_requests.size();
}
System.out.println("\nTotal motion C-SCAN: " + motion_sum);
}
public static void main(String... arg)
{
int pos = 35;
List<Integer> disk_request_list = Arrays.asList(100, 50, 10, 20, 75);
startCSCAN(pos, disk_request_list);
}
}