Java Code Examples for java.util.PriorityQueue#remove()

public static ArrayList<Long> primeFactorization(long n) {
  ArrayList<Long> factors = new ArrayList<>();
  if (n <= 0) throw new IllegalArgumentException();
  else if (n == 1) return factors;
  PriorityQueue<Long> divisorQueue = new PriorityQueue<>();
  divisorQueue.add(n);
  while (!divisorQueue.isEmpty()) {
    long divisor = divisorQueue.remove();
    if (isPrime(divisor)) {
      factors.add(divisor);
      continue;
    }
    long next_divisor = pollardRho(divisor);
    if (next_divisor == divisor) {
      divisorQueue.add(divisor);
    } else {
      divisorQueue.add(next_divisor);
      divisorQueue.add(divisor / next_divisor);
    }
  }
  return factors;
}
 

/**
 * retainAll(c) retains only those elements of c and reports true if changed
 */
public void testRetainAll() {
    PriorityQueue q = populatedQueue(SIZE);
    PriorityQueue p = populatedQueue(SIZE);
    for (int i = 0; i < SIZE; ++i) {
        boolean changed = q.retainAll(p);
        if (i == 0)
            assertFalse(changed);
        else
            assertTrue(changed);

        assertTrue(q.containsAll(p));
        assertEquals(SIZE - i, q.size());
        p.remove();
    }
}
 

static public MinimumSpanningTree build(TreeNode[] nodes, int[][] distances, int root) {
	MinimumSpanningTree mst = new MinimumSpanningTree(nodes[root]);
	PriorityQueue<Vertex> costList = new PriorityQueue<Vertex>();
	
	for(int i = 0; i < distances.length; i++) {
		if(i != root)
			costList.add(new Vertex(i, root, distances[i][root]));
	}
	
	while(!costList.isEmpty()) {
		Vertex next = costList.poll();
		nodes[next.to].addChild(nodes[next.id]);
		Vertex[] remains = costList.toArray(new Vertex[0]);
		for(int i = 0; i<remains.length; i++) {
			if(distances[remains[i].id][next.id] <= remains[i].value) {
				costList.remove(remains[i]);
				remains[i].to = next.id;
				remains[i].value = distances[remains[i].id][next.id];
				costList.add(remains[i]);
			}
		}
	}
	return mst;	
}
 

private void relaxEdges(Vertex [] graph,int vertex,int contractId, PriorityQueue queue,int sourceId){
	ArrayList<Integer> vertexList = graph[vertex].outEdges;
	ArrayList<Long> costList = graph[vertex].outECost;
	
	for(int i=0;i<vertexList.size();i++){
		int temp = vertexList.get(i);
		long cost = costList.get(i);
		if(graph[temp].contracted){
			continue;
		}
		if(checkId(graph,vertex,temp) || graph[temp].distance.distance > graph[vertex].distance.distance + cost){
			graph[temp].distance.distance = graph[vertex].distance.distance + cost;
			graph[temp].distance.contractId = contractId;
			graph[temp].distance.sourceId = sourceId;
			
			queue.remove(graph[temp]);
			queue.add(graph[temp]);
		}
	}
}
 

public boolean isPossibleDivide(int[] nums, int k) {
    int len = nums.length;
    if (len % k != 0) {
        return false;
    }

    PriorityQueue<Integer> minHeap = new PriorityQueue<>(len);
    for (int num : nums) {
        minHeap.offer(num);
    }

    while (!minHeap.isEmpty()) {
        Integer top = minHeap.poll();

        for (int i = 1; i < k; i++) {
            // 从 1 开始，正好需要移除 k - 1 个元素
            // i 正好就是相对于 top 的偏移
            if (!minHeap.remove(top + i)) {
                // 如果移除失败，说明划分不存在，直接返回 false 即可
                return false;
            }
        }
    }
    return true;
}
 

@Test
public void testContainmentRandomized() {

  for (int i = 0; i < LOOPS; i++) {

    List<Integer> randNums = genRandList(100);
    PriorityQueue<Integer> PQ = new PriorityQueue<>();
    BinaryHeap<Integer> pq = new BinaryHeap<>();
    for (int j = 0; j < randNums.size(); j++) {
      pq.add(randNums.get(j));
      PQ.add(randNums.get(j));
    }

    for (int j = 0; j < randNums.size(); j++) {

      int randVal = randNums.get(j);
      assertEquals(pq.contains(randVal), PQ.contains(randVal));
      pq.remove(randVal);
      PQ.remove(randVal);
      assertEquals(pq.contains(randVal), PQ.contains(randVal));
    }
  }
}
 

public void restoreModels(Map<CharacterInfoTab, ModelMap> states, int selectedIndex)
{
	CharacterInfoTab firstTab = (CharacterInfoTab) getComponentAt(selectedIndex);
	restoreTab(firstTab, states.get(firstTab));
	int oldSelectedIndex = getSelectedIndex();
	setSelectedIndex(selectedIndex);
	if (oldSelectedIndex == selectedIndex)
	{
		handleDisplayAware();
	}

	PriorityQueue<CharacterInfoTab> queue = new PriorityQueue<>(states.keySet().size(), this);
	queue.addAll(states.keySet());
	queue.remove(firstTab);

	while (!queue.isEmpty())
	{
		CharacterInfoTab infoTab = queue.poll();
		ModelMap models = states.get(infoTab);
		restoreQueue.add(submit(new RestoreModelsTask(infoTab, models)));
	}
}
 

/**
 * Removes an item to the global queue and updates its upload status.
 *
 * @param c            the current context
 * @param queue        the queue to update from
 * @param procedureUri the procedure in the queue
 * @param newStatus    the new upload status
 * @return true if the procedure was in the queue and updated
 */
public static boolean removeFromQueue(Context c, PriorityQueue<Uri> queue,
                                      Uri procedureUri, int newStatus) {
    if (QueueManager.isInQueue(queue, procedureUri)) {
        queue.remove(procedureUri);
        QueueManager.updateQueueInDB(c, queue);
        QueueManager.setProcedureUploadStatus(c, procedureUri, newStatus);
        return true;
    }
    return false;
}
 

/**
* Performs a depth first search (without backtracking) starting from the the given transformation
* @param queue
* @param transformation
*/
private void dfs(PriorityQueue<Object> queue, Transformation<?> transformation) {
    if (mustStop()) {
        return;
    }
    Transformation<?> next = expand(queue, transformation);
    if (next != null) {
        queue.remove(next.getIdentifier());
        dfs(queue, next);
    }
}
 

@Override
public Iterator<IntermediateSampleData<T>> sampleInPartition(Iterator<T> input) {
	if (numSamples == 0) {
		return emptyIntermediateIterable;
	}

	// This queue holds fixed number elements with the top K weight for current partition.
	PriorityQueue<IntermediateSampleData<T>> queue = new PriorityQueue<IntermediateSampleData<T>>(numSamples);
	int index = 0;
	IntermediateSampleData<T> smallest = null;
	while (input.hasNext()) {
		T element = input.next();
		if (index < numSamples) {
			// Fill the queue with first K elements from input.
			queue.add(new IntermediateSampleData<T>(random.nextDouble(), element));
			smallest = queue.peek();
		} else {
			double rand = random.nextDouble();
			// Remove the element with the smallest weight, and append current element into the queue.
			if (rand > smallest.getWeight()) {
				queue.remove();
				queue.add(new IntermediateSampleData<T>(rand, element));
				smallest = queue.peek();
			}
		}
		index++;
	}
	return queue.iterator();
}
 

private static long lockAndRunQueue(final AsyncServer server, final PriorityQueue<Scheduled> queue) {
    long wait = QUEUE_EMPTY;

    // find the first item we can actually run
    while (true) {
        Scheduled run = null;

        synchronized (server) {
            long now = SystemClock.elapsedRealtime();

            if (queue.size() > 0) {
                Scheduled s = queue.remove();
                if (s.time <= now) {
                    run = s;
                }
                else {
                    wait = s.time - now;
                    queue.add(s);
                }
            }
        }

        if (run == null)
            break;

        run.run();
    }

    server.postCounter = 0;
    return wait;
}
 

/**
 * size changes when elements added and removed
 */
public void testSize() {
    PriorityQueue q = populatedQueue(SIZE);
    for (int i = 0; i < SIZE; ++i) {
        assertEquals(SIZE - i, q.size());
        q.remove();
    }
    for (int i = 0; i < SIZE; ++i) {
        assertEquals(i, q.size());
        q.add(new Integer(i));
    }
}
 

@Test
public void testRandomizedRemoving() {

  for (int i = 0; i < LOOPS; i++) {

    int sz = i;
    List<Integer> randNums = genRandList(sz);
    PriorityQueue<Integer> pq1 = new PriorityQueue<>();
    BinaryHeap<Integer> pq2 = new BinaryHeap<>();

    // Add all the elements to both priority queues
    for (Integer value : randNums) {
      pq1.offer(value);
      pq2.add(value);
    }

    Collections.shuffle(randNums);
    int index = 0;

    while (!pq1.isEmpty()) {

      int removeNum = randNums.get(index++);

      assertTrue(pq2.isMinHeap(0));
      assertEquals(pq1.size(), pq2.size());
      assertEquals(pq1.peek(), pq2.peek());
      pq1.remove(removeNum);
      pq2.remove(removeNum);
      assertEquals(pq1.peek(), pq2.peek());
      assertEquals(pq1.size(), pq2.size());
      assertTrue(pq2.isMinHeap(0));
    }
  }
}
 

private List<Bucket> bucketLayers(final List<LayerData> sortedLayerList) {

        final PriorityQueue<Bucket> bucketQueue = new PriorityQueue<>(numberOfBuckets);

        int layerIndex = sortedLayerList.size() - 1;
        for (int bucketIndex = 0; bucketIndex < numberOfBuckets; bucketIndex++) {
            if (layerIndex >= 0) {
                bucketQueue.add(new Bucket(sortedLayerList.get(layerIndex)));
                layerIndex--;
            } else {
                break;
            }
        }

        Bucket bucket;
        for (; layerIndex >= 0; layerIndex--) {
            bucket = bucketQueue.remove();
            bucket.addLayer(sortedLayerList.get(layerIndex));
            bucketQueue.add(bucket);
        }

        final List<Bucket> sortedBucketList = new ArrayList<>(numberOfBuckets);
        sortedBucketList.addAll(bucketQueue.stream().collect(Collectors.toList()));
        Collections.sort(sortedBucketList);

        return sortedBucketList;
    }
 

/**
 * Replace a given path with that of this candidate move.
 *
 * @param openMap The list of available nodes.
 * @param openMapQueue The queue of available nodes.
 * @param f The heuristic values for A*.
 * @param sh A {@code SearchHeuristic} to apply.
 */
public void improve(HashMap<String, PathNode> openMap,
                    PriorityQueue<PathNode> openMapQueue,
                    HashMap<String, Integer> f,
                    SearchHeuristic sh) {
    PathNode best = openMap.get(dst.getId());
    if (best != null) {
        openMap.remove(dst.getId());
        openMapQueue.remove(best);
    }
    add(openMap, openMapQueue, f, sh);
}
 

public void remove(PrioritizedSplitRunner split)
{
    checkArgument(split != null, "split is null");
    lock.lock();
    try {
        for (PriorityQueue<PrioritizedSplitRunner> level : levelWaitingSplits) {
            level.remove(split);
        }
    }
    finally {
        lock.unlock();
    }
}
 

/**
 * Sample algorithm for the second phase. This operation should be executed as the UDF of
 * an all reduce operation.
 *
 * @param input The intermediate sample output generated in the first phase.
 * @return The sampled output.
 */
public Iterator<T> sampleInCoordinator(Iterator<IntermediateSampleData<T>> input) {
	if (numSamples == 0) {
		return emptyIterable;
	}

	// This queue holds fixed number elements with the top K weight for the coordinator.
	PriorityQueue<IntermediateSampleData<T>> reservoir = new PriorityQueue<IntermediateSampleData<T>>(numSamples);
	int index = 0;
	IntermediateSampleData<T> smallest = null;
	while (input.hasNext()) {
		IntermediateSampleData<T> element = input.next();
		if (index < numSamples) {
			// Fill the queue with first K elements from input.
			reservoir.add(element);
			smallest = reservoir.peek();
		} else {
			// If current element weight is larger than the smallest one in queue, remove the element
			// with the smallest weight, and append current element into the queue.
			if (element.getWeight() > smallest.getWeight()) {
				reservoir.remove();
				reservoir.add(element);
				smallest = reservoir.peek();
			}
		}
		index++;
	}
	final Iterator<IntermediateSampleData<T>> itr = reservoir.iterator();

	return new Iterator<T>() {
		@Override
		public boolean hasNext() {
			return itr.hasNext();
		}

		@Override
		public T next() {
			return itr.next().getElement();
		}

		@Override
		public void remove() {
			itr.remove();
		}
	};
}
 

public void computeCOF(ArrayList<COFObject> cofobjectList, int k, DistanceMeasure measure) {

		// define a list of knn for each cof object
		PriorityQueue<COFKnn> knnList = new PriorityQueue<COFKnn>();

		// reset pcl, kDist, and deviation
		double pcl = 0.0;
		double kDist = 0.0;
		double deviation = 0.0;

		for (COFObject cofobject : cofobjectList) {// for all objects in the dataset
			double distance = Double.POSITIVE_INFINITY;
			// compute the distance to current object
			distance = measure.calculateDistance(this.getValues(), cofobject.getValues());
			COFKnn cOFKnn = new COFKnn(cofobject, distance);
			// determine if cofobject is on of the nearest neighbors to current object
			if (knnList.size() < k) {
				knnList.offer(cOFKnn);
			} else if (distance < knnList.peek().getDistance()) {
				knnList.remove();
				knnList.offer(cOFKnn);
			}
			// if the cofobject has the same class label, add its distance to deviation
			if (this.getLabel() == cofobject.getLabel()) {
				deviation += distance;
			}

		}
		this.setDeviation(deviation); // save deviation

		// compute pcl to current object
		for (COFKnn cofKnn : knnList) {
			kDist += measure.calculateDistance(getValues(), cofKnn.getCofobject().getValues());
			if (this.getLabel() == cofKnn.getCofobject().getLabel()) {
				pcl++;
			}
		}

		this.setPcl(pcl); // save pcl
		this.setCOF(pcl); // save the initial cof based on pcl
		this.setKDist(kDist); // save kDist

	}
 

public double[] medianSlidingWindow(int[] nums, int k) {
    int len = nums.length;
    int windowLen = len - k + 1;
    double[] res = new double[windowLen];
    PriorityQueue<Integer> maxHeap = new PriorityQueue<>(Collections.reverseOrder());
    PriorityQueue<Integer> minHeap = new PriorityQueue<>();
    // 下一个要填的值
    int next = 0;
    // 循环不变量：
    // 1、maxHeap 的堆顶小于等于 minHeap 的堆顶
    // 2、maxHeap.size() = minHeap.size() 或者
    // 3、maxHeap.size() = minHeap.size() + 1，这样中位数就在 maxHeap 的堆顶
    for (int i = 0; i < len; i++) {
        // 步骤 1：加入元素的时候，保持第 1、2、3 点
        maxHeap.add(nums[i]);
        minHeap.add(maxHeap.poll());
        if ((i & 1) == 0) {
            // 这个语义太难理解：
            // 如果还未添加 nums[i] 之前是偶数，那么添加 nums[i] 的效果是 maxHeap 多 1 个元素
            maxHeap.add(minHeap.poll());
        }
        // 步骤 2：移除窗口外的值，移除滑动窗口的左边界
        // 假设修正法：默认是大顶堆移除了一个元素
        if (i >= k) {
            int removeFrom = 1;
            // 如果不是在最小堆，就在最大堆
            if (minHeap.contains(nums[i - k])) {
                minHeap.remove(nums[i - k]);
                removeFrom = 0;
            } else {
                maxHeap.remove(nums[i - k]);
            }
            // 步骤 3：保持第 2、3 点
            if ((i & 1) == 1 && removeFrom == 1) {
                maxHeap.add(minHeap.poll());
            }
            if ((i & 1) == 0 && removeFrom == 0) {
                minHeap.add(maxHeap.poll());
            }
        }
        // 步骤 4：求滑动窗口的中位数
        if (i >= k - 1) {
            if (maxHeap.size() > minHeap.size()) {
                res[next] = maxHeap.peek();
            } else {
                res[next] = minHeap.peek() / 2.0 + maxHeap.peek() / 2.0;
            }
            next++;
        }
    }
    return res;
}
 

@Test
public void testPQReusability() {

  List<Integer> SZs = genUniqueRandList(LOOPS);

  PriorityQueue<Integer> PQ = new PriorityQueue<>();
  BinaryHeapQuickRemovals<Integer> pq = new BinaryHeapQuickRemovals<>();

  for (int sz : SZs) {

    pq.clear();
    PQ.clear();

    List<Integer> nums = genRandList(sz);
    for (int n : nums) {
      pq.add(n);
      PQ.add(n);
    }

    Collections.shuffle(nums);

    for (int i = 0; i < sz / 2; i++) {

      // Sometimes add a new number into the BinaryHeapQuickRemovals
      if (0.25 < Math.random()) {
        int randNum = (int) (Math.random() * 10000);
        PQ.add(randNum);
        pq.add(randNum);
      }

      int removeNum = nums.get(i);

      assertTrue(pq.isMinHeap(0));
      assertEquals(PQ.size(), pq.size());
      assertEquals(PQ.peek(), pq.peek());

      PQ.remove(removeNum);
      pq.remove(removeNum);

      assertEquals(PQ.peek(), pq.peek());
      assertEquals(PQ.size(), pq.size());
      assertTrue(pq.isMinHeap(0));
    }
  }
}