数组去重

package cn.laojiu.demo16;

import java.util.Arrays;

public class For {
    public static void main(String[] args) {
        int[] arr = { 1, 2, 3, 4, 2, 1 };
        for (int i = 0; i < arr.length; i++) {
            for (int y = arr.length - 1; y > i; y--) {
                if (arr[i] == arr[y]) {        //判断是否存在重复
                    for (int j = y; j < arr.length - 1; j++) {    
                        arr[j] = arr[j + 1];
                    }
                    arr = Arrays.copyOf(arr, arr.length - 1);    //数组缩小
                }
            }
        }
        System.out.println(Arrays.toString(arr));
    }
}