Class ArrayUtils


  • public class ArrayUtils
    extends java.lang.Object
    Utility class for sorting arrays etc.
    • Constructor Summary

      Constructors 
      Constructor Description
      ArrayUtils()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static void sort​(int[] keys, int[] values)
      Sorts the keys in an increasing order.
      static void sort​(int[] keys, int[] values, int offset, int length)
      Sorts a range from the keys in an increasing order.
      static void sortDesc​(long[] keys, int[] values)
      Sorts the keys in an decreasing order.
      static void sortDesc​(long[] keys, int[] values, long[] tmpa, int[] tmpb)
      Sorts the keys in an decreasing order.
      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ArrayUtils

        public ArrayUtils()
    • Method Detail

      • sort

        public static void sort​(int[] keys,
                                int[] values)
        Sorts the keys in an increasing order. Elements key[i] and values[i] are always swapped together in the corresponding arrays.

        A mixture of several sorting algorithms is used:

        A radix sort performs better on the numeric data we sort, but requires additional storage to perform the sorting. Therefore only the not-very-large parts produced by a quick sort are sorted with radix sort. An insertion sort is used to sort the smallest arrays, where the the overhead of the radix sort is also bigger

        Parameters:
        keys - the keys for sorting
        values - the values to be swapped with the corresponding keys
      • sortDesc

        public static void sortDesc​(long[] keys,
                                    int[] values)
        Sorts the keys in an decreasing order. Elements key[i] and values[i] are always swapped together in the corresponding arrays.

        A mixture of several sorting algorithms is used:

        A radix sort performs better on the numeric data we sort, but requires additional storage to perform the sorting. Therefore only the not-very-large parts produced by a quick sort are sorted with radix sort. An insertion sort is used to sort the smallest arrays, where the the overhead of the radix sort is also bigger

        Parameters:
        keys - the keys for sorting
        values - the values to be swapped with the corresponding keys
      • sortDesc

        public static void sortDesc​(long[] keys,
                                    int[] values,
                                    long[] tmpa,
                                    int[] tmpb)
        Sorts the keys in an decreasing order. Elements key[i] and values[i] are always swapped together in the corresponding arrays.

        A mixture of several sorting algorithms is used:

        A radix sort performs better on the numeric data we sort, but requires additional storage to perform the sorting. Therefore only the not-very-large parts produced by a quick sort are sorted with radix sort. An insertion sort is used to sort the smallest arrays, where the the overhead of the radix sort is also bigger

        This version of the method allows the temporarily needed arrays for the radix sort to be provided externally - tempa and tempb. This saves unnecessary array creation and cleanup

        Parameters:
        keys - the keys for sorting
        values - the values to be swapped with the corresponding keys
        tmpa - a temporary buffer at least as big as the keys
        tmpb - a temporary buffer at least as big as the keys/values
      • sort

        public static void sort​(int[] keys,
                                int[] values,
                                int offset,
                                int length)
        Sorts a range from the keys in an increasing order. Elements key[i] and values[i] are always swapped together in the corresponding arrays.

        A mixture of several sorting algorithms is used:

        A radix sort performs better on the numeric data we sort, but requires additional storage to perform the sorting. Therefore only the not-very-large parts produced by a quick sort are sorted with radix sort. An insertion sort is used to sort the smallest arrays, where the the overhead of the radix sort is also bigger

        Parameters:
        keys - the keys for sorting
        values - the values to be swapped with the corresponding keys
        offset - where in the arrays to start sorting
        length - how many keys (and values) from the offset to sort