替换Java列表List中重复元素为一个元素

　　如果一个列表List中包含重复的元素，它们应该用单个元素替换，而且元素的顺序不应该改变。

import java.util.ArrayList;

import java.util.List;

import java.util.Objects;

/**

 * <b>(**) Eliminate consecutive duplicates of list elements</b>

 * <p>If a list contains repeated elements they should be replaced with a single copy of the element.

 * The order of the elements should not be changed.</p>

 * <p>

 * <pre>

 *     compress(Arrays.asList(a,a,a,a,b,c,c,a,a,d,e,e,e,e))

 *     [a,b,c,d,e]

 * </pre>

*/

public class P08 {

    public static <T> List<T> compress(List<T> list) {

        Objects.requireNonNull(list, "Please make sure list is not null");

        List<T> result = new ArrayList<>();

        T lastElement = null;

        for (T e : list) {

            if (!Objects.equals(lastElement, e)) {

                result.add(e);

            lastElement = e;

        return result;