Class LongHeap

  • public abstract class LongHeap
    extends Object
    A heap that stores longs; a primitive priority queue that like all priority queues maintains a partial ordering of its elements such that the least element can always be found in constant time. Put()'s and pop()'s require log(size). This heap provides unbounded growth via push(long), and bounded-size insertion based on its nominal maxSize via insertWithOverflow(long). The heap may be either a min heap, in which case the least element is the smallest integer, or a max heap, when it is the largest, depending on the Order parameter.
    NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
    • Method Detail

      • lessThan

        public abstract boolean lessThan​(long a,
                                         long b)
        Determines the ordering of objects in this priority queue. Subclasses must define this one method.
        true iff parameter a is less than parameter b.
      • push

        public final long push​(long element)
        Adds a value in log(size) time. Grows unbounded as needed to accommodate new values.
        the new 'top' element in the queue.
      • insertWithOverflow

        public boolean insertWithOverflow​(long value)
        Adds a value to an LongHeap in log(size) time. If the number of values would exceed the heap's maxSize, the least value is discarded.
        whether the value was added (unless the heap is full, or the new value is less than the top value)
      • top

        public final long top()
        Returns the least element of the LongHeap in constant time. It is up to the caller to verify that the heap is not empty; no checking is done, and if no elements have been added, 0 is returned.
      • pop

        public final long pop()
        Removes and returns the least element of the PriorityQueue in log(size) time.
        IllegalStateException - if the LongHeap is empty.
      • updateTop

        public final long updateTop​(long value)
        Replace the top of the pq with newTop. Should be called when the top value changes. Still log(n) worst case, but it's at least twice as fast to
        instead of
        Calling this method on an empty LongHeap has no visible effect.
        value - the new element that is less than the current top.
        the new 'top' element after shuffling the heap.
      • size

        public final int size()
        Returns the number of elements currently stored in the PriorityQueue.
      • clear

        public final void clear()
        Removes all entries from the PriorityQueue.
      • pushAll

        public void pushAll​(LongHeap other)
      • get

        public long get​(int i)
        Return the element at the ith location in the heap array. Use for iterating over elements when the order doesn't matter. Note that the valid arguments range from [1, size].
      • getHeapArray

        protected final long[] getHeapArray()
        This method returns the internal heap array.
        NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.