Java List Permutate permutate(List src)

Description

permutate

License

Open Source License

Declaration

public static <T> List<List<T>> permutate(List<T> src) 

Method Source Code

//package com.java2s;
/*/*from ww  w.  ja  va  2 s. co m*/
 * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.util.ArrayList;
import java.util.List;

public class Main {
    public static <T> List<List<T>> permutate(List<T> src) {
        if (src.size() <= 1) {
            List<List<T>> al = new ArrayList<>();
            al.add(src);
            return al;
        }

        List<List<T>> result = new ArrayList<>();
        for (int i = 0; i < src.size(); i++) {
            List<T> copy = new ArrayList<>(src);
            T el = copy.remove(i);

            for (List<T> perm : permutate(copy)) {
                List<T> c = new ArrayList<>(perm);
                c.add(0, el);
                result.add(c);
            }
        }

        return result;
    }
}

Related

1. perm(List l)
2. permsList(List topList)
3. permutation(List list1, List list2, String token)
4. permutation(String prefix, String s, List list)
5. permutations(List list)
6. permutations(List listings)