Files
aston-team-project/app/src/main/java/ru/project/finder/StudentOccurrenceIndexFinder.java
T

133 lines
3.5 KiB
Java

package ru.project.finder;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import ru.project.collection.MyLinkedList;
import ru.project.collection.MyList;
import ru.project.student.Student;
public class StudentOccurrenceIndexFinder {
public int[] findOccurrences(MyList<Student> students, Student target) {
if (students == null) {
throw new IllegalArgumentException();
}
if (target == null) {
throw new IllegalArgumentException();
}
if (students.isEmpty()) {
return new int[0];
}
int size = students.size();
int threadCount = calculateThreadCount(size);
int chunkSize = countChunkSize(size, threadCount);
ExecutorService executor = Executors.newFixedThreadPool(threadCount);
MyList<Future<MyList<Integer>>> futures = new MyLinkedList<>();
for (int i = 0; i < threadCount; i++) {
int fromIndex = i * chunkSize;
int toIndex = Math.min(fromIndex + chunkSize, size);
if (fromIndex >= toIndex) {
break;
}
final int start = fromIndex;
final int end = toIndex;
Future<MyList<Integer>> future =
executor.submit(
() -> {
return findInRange(students, target, start, end);
});
futures.add(future);
}
MyList<Integer> allIndices = new MyLinkedList<>();
try {
for (int i = 0; i < futures.size(); i++) {
Future<MyList<Integer>> future = futures.get(i);
MyList<Integer> partialResult = future.get();
if (partialResult != null) {
for (int j = 0; j < partialResult.size(); j++) {
allIndices.add(partialResult.get(j));
}
}
}
} catch (Exception e) {
throw new RuntimeException("Ошибка при поиске", e);
} finally {
executor.shutdown();
}
sortList(allIndices);
int[] resultArray = new int[allIndices.size()];
for (int i = 0; i < allIndices.size(); i++) {
resultArray[i] = allIndices.get(i);
}
return resultArray;
}
private void sortList(MyList<Integer> list) {
if (list.size() <= 1) return;
MyList<Integer> sorted = new MyLinkedList<>();
for (int i = 0; i < list.size(); i++) {
int value = list.get(i);
int insertIndex = 0;
while (insertIndex < sorted.size()) {
if (sorted.get(insertIndex) > value) {
break;
}
insertIndex++;
}
MyList<Integer> temp = new MyLinkedList<>();
for (int k = 0; k < insertIndex; k++) {
temp.add(sorted.get(k));
}
temp.add(value);
for (int k = insertIndex; k < sorted.size(); k++) {
temp.add(sorted.get(k));
}
sorted = temp;
}
while (!list.isEmpty()) {
list.remove(0);
}
for (int i = 0; i < sorted.size(); i++) {
list.add(sorted.get(i));
}
}
private int calculateThreadCount(int size) {
int processors = Runtime.getRuntime().availableProcessors();
return Math.min(processors, size);
}
private int countChunkSize(int size, int threadCount) {
if (threadCount == 0) return 0;
return (size + threadCount - 1) / threadCount;
}
private MyList<Integer> findInRange(
MyList<Student> students, Student target, int fromIndex, int toIndex) {
MyList<Integer> foundIndices = new MyLinkedList<>();
for (int i = fromIndex; i < toIndex; i++) {
Student current = students.get(i);
if (current != null && current.equals(target)) {
foundIndices.add(i);
}
}
return foundIndices;
}
}