Android Open Source - BT4Android-trunk D Sutil

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License

The source code is released under:

Apache License

Java Source Code

package com.love.qsort;
/* w w  w .  j  a v  a2  s  .co m*/
import java.util.*;
import java.math.*;

class DSutil<E> {

  public static <E> void swap(E[] A, int p1, int p2) {
    E temp = A[p1];
    A[p1] = A[p2];
    A[p2] = temp;
  }

  /** Randomly permute the Objects in an array.
  @param A The array
   */

  //int version
  //Randomly permute the values of array "A"
  static void permute(int[] A) {
    for (int i = A.length; i > 0; i--) // for each i
      swap(A, i-1, DSutil.random(i));  //   swap A[i-1] with
  }                                    //   a random element

  public static void swap(int[] A, int p1, int p2) {
    int temp = A[p1];
    A[p1] = A[p2];
    A[p2] = temp;
  }

  static <E> void permute(E[] A) {
    for (int i = A.length; i > 0; i--) // for each i
      swap(A, i-1, DSutil.random(i));  //   swap A[i-1] with
  }                                    //   a random element

  static void MinMax(int A[], int l, int r, int Out[]) {
    if (l == r) {        // n=1
      Out[0] = A[r];
      Out[1] = A[r];
    }
    else if (l+1 == r) { // n=2
      Out[0] = Math.min(A[l], A[r]);
      Out[1] = Math.max(A[l], A[r]);
    }
    else {               // n>2
      int[] Out1 = new int[2];
      int[] Out2 = new int[2];
      int mid = (l + r)/2;
      MinMax(A, l, mid, Out1);
      MinMax(A, mid+1, r, Out2);
      Out[0] = Math.min(Out1[0], Out2[0]);
      Out[1] = Math.max(Out1[1], Out2[1]);
    }
  }

  static private Random value = new Random(); // Hold the Random class object

  static int random(int n) {
    return Math.abs(value.nextInt()) % n;
  }

}

Java Source Code List

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