线程池：队列容量、扩容与拒绝策略如何决定结果

import java.util.*;

public class Main {
    record Task(long arrival, long duration) {
        Task { if (arrival<0 || duration<=0) throw new IllegalArgumentException(); }
    }
    static long[] simulate(int workers, int queueCapacity, List<Task> tasks) {
        if (workers<=0 || queueCapacity<0) throw new IllegalArgumentException();
        Objects.requireNonNull(tasks);
        PriorityQueue<Long> available = new PriorityQueue<>(Collections.nCopies(workers,0L));
        PriorityQueue<Long> unfinished = new PriorityQueue<>();
        long[] result = new long[tasks.size()];
        long previous=0, capacity=(long)workers+queueCapacity;
        for (int i=0;i<tasks.size();i++) {
            Task task=Objects.requireNonNull(tasks.get(i));
            if (task.arrival()<previous) throw new IllegalArgumentException("unsorted arrivals");
            previous=task.arrival();
            while (!unfinished.isEmpty() && unfinished.peek()<=task.arrival()) unfinished.poll();
            // 同时刻先完成旧任务，再判断新任务能否进入系统。
            if (unfinished.size()>=capacity) { result[i]=-1; continue; }
            long start=Math.max(task.arrival(),available.peek());
            long finish=Math.addExact(start,task.duration()); // 溢出时拒绝伪造时间。
            available.poll(); available.add(finish); // 将任务安排给最早可用工作者。
            unfinished.add(finish); result[i]=finish;
        }
        return result;
    }
    static void check(long[] actual, long... expected) {
        if (!Arrays.equals(actual,expected)) throw new AssertionError(Arrays.toString(actual));
    }
    public static void main(String[] args) {
        check(simulate(1,1,List.of(new Task(0,5),new Task(1,5),new Task(2,1),new Task(5,1))),5,10,-1,11);
        check(simulate(2,0,List.of(new Task(0,3),new Task(0,4),new Task(0,1))),3,4,-1);
        check(simulate(1,0,List.of(new Task(0,2),new Task(2,1))),2,3);
        check(simulate(1,1,List.of()));
        check(simulate(2,1,List.of(new Task(0,9),new Task(0,2),new Task(1,1))),9,2,3);
        try { simulate(1,0,List.of(new Task(Long.MAX_VALUE,1))); throw new AssertionError(); }
        catch (ArithmeticException expected) { }
        try { simulate(1,0,List.of(new Task(2,1),new Task(1,1))); throw new AssertionError(); }
        catch (IllegalArgumentException expected) { }
        System.out.println("PASS 7");
    }
}