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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.*;
/**
* Class for rotating arrays
*/
public class Rotate
{
/*
* There are many thing you can change in this class to adapt it, for example,
* if you want in-place rotation, which probabily is a bit slower (even though
* it is less naïve), you can reverse the array, split it at the index 'steps',
* and reverse those partitions and the concatinate back again, of cause, you
* would only reverse parts of the array, not split and concatinate it.
* You could also reverse the array while rotating it, either reverse the
* input or the output.
*/
£<for T in boolean char byte short int long float double T; do
P= O="$T" cast=
£>[ $T = T ] && P="<T> " O=Object cast="(T[])"
/**
* Rotates an array
*
* @param items The array to rotate
* @param steps The number of steps to higher index to rotate elements
* @return The array rotated
*/
£>[ $T = T ] &&
@SuppressWarnings("unchecked")
public static £{P}£{T}[] rotateClone(£{T}[] items, int steps)
{
£{O}[] rc = new £{O}[items.length];
int n = items.length;
if ((n & -n) == n) /* power of 2 */
for (int i = 0, m = n - 1; i < n; i++)
rc[(steps + i) & m] = items[i];
else
for (int i = 0; i < n; i++)
rc[(steps + i) % n] = items[i];
return £{cast}rc;
}
£>done
}
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