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-rw-r--r--src/algorithms/shuffling/SattoloShuffle.java50
1 files changed, 50 insertions, 0 deletions
diff --git a/src/algorithms/shuffling/SattoloShuffle.java b/src/algorithms/shuffling/SattoloShuffle.java
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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.arrays;
+
+import java.util.Random;
+
+
+/**
+ * Bias free array shuffling class using Sattolo Cycles.<br/>
+ * The is probably the best possible shuffling algorithm.
+ */
+public class KnuthShuffle
+{
+£>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 i = array.length, j;
+ for (;;)
+ {
+ if (i-- == 1)
+ break;
+
+ £{T} temp = array[i];
+ array[i] = array[j = random.nextInt(i)];
+ array[j] = temp;
+ }
+ }
+£>done
+}
+