Java Array Shuffle shuffle(T[] array)

Description

shuffle

License

Open Source License

Declaration

static public <T> T[] shuffle(T[] array) 

Method Source Code

//package com.java2s;
/*/*from  w  w  w  . ja v  a  2s. c o  m*/
 * The MIT License
 *
 * Copyright 2014 q13000412.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

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

import java.util.Random;

public class Main {
    final static private Random rand = new Random();

    static public <T> T[] shuffle(T[] array) {
        T[] nArr = array.clone();

        List<Integer> keys = new ArrayList<>(array.length);

        for (int i = 0; i < array.length; ++i)
            keys.add(i);

        for (T obj : array) {
            int i = rand(0, keys.size());
            int index = keys.get(i);

            keys.remove(i);

            nArr[index] = obj;
        }

        return nArr;
    }

    static public int rand(int min, int max) {
        return rand.nextInt(max - min) + min;
    }
}

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