输入一个数组，输出数组的不同顺序组合，该组合是唯一的。思路和编码如下。

package com.javaTest;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Random;
import java.util.UUID;

public class JavaTest {
	public static void main(String[] args) {
		System.out.println("Hello World!");
		int[] nums=new int[] {1,2,3,4,5};
		List<ArrayList<CustIntGroup>> diffGroupIntegerList = getDiffGroupIntegerList(nums);
		System.out.println(diffGroupIntegerList);
		ArrayList<Integer> arrayList = new ArrayList<Integer>();
		arrayList.add(1);
		arrayList.add(2);
		arrayList.add(2);
		Boolean checkIntArrEleIsUnique = checkIntArrEleIsUnique(arrayList);
		System.out.println(checkIntArrEleIsUnique);
	}
	public static List<ArrayList<CustIntGroup>> getDiffGroupIntegerList(int[] nums){
		if(nums==null) {
			return null;
		}
		if(nums.length==0) {
			return null;
		}
		if(nums.length<1 || nums.length>6) {
			return null;
		}
		HashSet<Integer> hashSet = new HashSet<Integer>();
		for (int i = 0; i < nums.length; i++) {
			int j = nums[i];
			if(j<0 || j>10) {
				return null;
			}
			hashSet.add(j);
		}
		if(hashSet.size()<nums.length) {
			return null;
		}
		List<ArrayList<CustIntGroup>> arrayList = new ArrayList<ArrayList<CustIntGroup>>();
		Random random = new Random();
		HashSet<CustIntGroup> hashSet2 = new HashSet<CustIntGroup>();
		int count=0;
		while(true) {
			ArrayList<Integer> arrayList3 = new ArrayList<Integer>();
			for (int j = 0; j < nums.length; j++) {
				CustIntGroup custIntGroup = new CustIntGroup();
				custIntGroup.setId(UUID.randomUUID().toString());
				int nextInt = random.nextInt(nums.length);
				int i = nums[nextInt];
				arrayList3.add(i);
				if(arrayList3.size()<nums.length) {
					continue;
				}
				if(checkIntArrEleIsUnique(arrayList3)) {
					custIntGroup.setIntArr(arrayList3);
				}
				hashSet2.add(custIntGroup);
			}
			ArrayList<CustIntGroup> arrayList2 = new ArrayList<CustIntGroup>();
			hashSet2.forEach(e->{
				arrayList2.add(e);
			});
			arrayList.add(arrayList2);
			count++;
			if(count>1000000) {
				break;
			}
		}
		return arrayList;
	}
	public static Boolean checkIntArrEleIsUnique(List<Integer> intList) {
		if(intList==null) {
			return null;
		}
		if(intList.isEmpty()) {
			return null;
		}
		HashSet<Integer> hashSet = new HashSet<Integer>();
		intList.forEach(e->{
			hashSet.add(e);
		});
		if(hashSet.size()<intList.size()) {
			return false;
		}
		return true;
	}
}
class CustIntGroup{
	private String id;
	private List<Integer> intArr;
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public List<Integer> getIntArr() {
		return intArr;
	}
	public void setIntArr(List<Integer> intArr) {
		this.intArr = intArr;
	}
	@Override
	public int hashCode() {
		return Objects.hash(intArr);
	}
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		CustIntGroup other = (CustIntGroup) obj;
		return Objects.equals(intArr, other.intArr);
	}
	
}