org.jgrapht.util.ArrayUtil Maven / Gradle / Ivy
/*
* (C) Copyright 2021-2021, by Hannes Wellmann and Contributors.
*
* JGraphT : a free Java graph-theory library
*
* See the CONTRIBUTORS.md file distributed with this work for additional
* information regarding copyright ownership.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0, or the
* GNU Lesser General Public License v2.1 or later
* which is available at
* http://www.gnu.org/licenses/old-licenses/lgpl-2.1-standalone.html.
*
* SPDX-License-Identifier: EPL-2.0 OR LGPL-2.1-or-later
*/
package org.jgrapht.util;
/**
* Utility class to simplify handling of arrays.
*
* @author Hannes Wellmann
*
*/
public class ArrayUtil
{
private ArrayUtil()
{ // static use only
}
/**
* Reverses the order of the elements in the specified range within the given array.
*
* @param the type of elements in the array
* @param arr the array
* @param from the index of the first element (inclusive) inside the range to reverse
* @param to the index of the last element (inclusive) inside the range to reverse
*/
public static final void reverse(V[] arr, int from, int to)
{
for (int i = from, j = to; i < j; ++i, --j) {
swap(arr, i, j);
}
}
/**
* Reverses the order of the elements in the specified range within the given array.
*
* @param arr the array
* @param from the index of the first element (inclusive) inside the range to reverse
* @param to the index of the last element (inclusive) inside the range to reverse
*/
public static final void reverse(int[] arr, int from, int to)
{
for (int i = from, j = to; i < j; ++i, --j) {
int tmp = arr[j];
arr[j] = arr[i];
arr[i] = tmp;
}
}
/**
* Swaps the two elements at the specified indices in the given array.
*
* @param the type of elements in the array
* @param arr the array
* @param i the index of the first element
* @param j the index of the second element
*/
public static final void swap(V[] arr, int i, int j)
{
V tmp = arr[j];
arr[j] = arr[i];
arr[i] = tmp;
}
}