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/**
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package algorithms.shuffling;
import java.util.Random;
/**
* Bias free array shuffling class aiming to imitate naïve shuffling as preformed by humans
*/
public class HumanShuffle
{
£>for T in boolean char byte short int long float double Object; do
/**
* Shuffles an array
*
* @param array The array to shuffle
* @param random The random generator to use
*/
public static void shuffle(£{T}[] array, Random random)
{
int n;
if ((n = array.length) < 2)
return;
int min = (int)(random.nextGaussian() * n) >> 1;
if (min < 0)
min = n - min;
else
min += n;
int k = 0;
while ((k++ < min) || (random.nextInt(2) == 0))
{
int i = random.nextInt(n);
int j = random.nextInt(n);
if (i == j)
j = (j + 1) % n;
£{T} temp = array[i];
array[i] = array[j];
array[j] = temp;
}
}
£>done
}
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