Package it.unimi.dsi.fastutil.ints

Class IntIndirectHeaps

java.lang.Object
it.unimi.dsi.fastutil.ints.IntIndirectHeaps
public final class IntIndirectHeaps extends Object
A class providing static methods and objects that do useful things with indirect heaps.

An indirect heap is an extension of a semi-indirect heap using also an inversion array of the same length as the reference array, satisfying the relation heap[inv[i]]==i when inv[i]>=0, and inv[heap[i]]==i for all elements in the heap.

  • Method Summary

    Modifier and Type
    Method
    Description
    static int
    downHeap(int[] refArray, int[] heap, int[] inv, int size, int i, IntComparator c)
    Moves the given element down into the indirect heap until it reaches the lowest possible position.
    static void
    makeHeap(int[] refArray, int[] heap, int[] inv, int size, IntComparator c)
    Creates an indirect heap from a given index array.
    static void
    makeHeap(int[] refArray, int offset, int length, int[] heap, int[] inv, IntComparator c)
    Creates an indirect heap in the given array.
    static int
    upHeap(int[] refArray, int[] heap, int[] inv, int size, int i, IntComparator c)
    Moves the given element up in the indirect heap until it reaches the highest possible position.

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • downHeap

      public static int downHeap(int[] refArray, int[] heap, int[] inv, int size, int i, IntComparator c)
      Moves the given element down into the indirect heap until it reaches the lowest possible position.
      Parameters:
      refArray - the reference array.
      heap - the indirect heap (starting at 0).
      inv - the inversion array.
      size - the number of elements in the heap.
      i - the index in the heap of the element to be moved down.
      c - a type-specific comparator, or null for the natural order.
      Returns:
      the new position in the heap of the element of heap index i.

    • upHeap

      public static int upHeap(int[] refArray, int[] heap, int[] inv, int size, int i, IntComparator c)
      Moves the given element up in the indirect heap until it reaches the highest possible position. Note that in principle after this call the heap property may be violated.
      Parameters:
      refArray - the reference array.
      heap - the indirect heap (starting at 0).
      inv - the inversion array.
      size - the number of elements in the heap.
      i - the index in the heap of the element to be moved up.
      c - a type-specific comparator, or null for the natural order.
      Returns:
      the new position in the heap of the element of heap index i.

    • makeHeap

      public static void makeHeap(int[] refArray, int offset, int length, int[] heap, int[] inv, IntComparator c)
      Creates an indirect heap in the given array.
      Parameters:
      refArray - the reference array.
      offset - the first element of the reference array to be put in the heap.
      length - the number of elements to be put in the heap.
      heap - the array where the heap is to be created.
      inv - the inversion array.
      c - a type-specific comparator, or null for the natural order.

    • makeHeap

      public static void makeHeap(int[] refArray, int[] heap, int[] inv, int size, IntComparator c)
      Creates an indirect heap from a given index array.
      Parameters:
      refArray - the reference array.
      heap - an array containing indices into refArray.
      inv - the inversion array.
      size - the number of elements in the heap.
      c - a type-specific comparator, or null for the natural order.