非递减子序列

/*
 * 思路：
 * 使用Java Stream API进行递归，通过维护一个列表来构建递增子序列。
 * 使用set去重，确保序列的唯一性。
 */
import java.util.*;
import java.util.stream.Collectors;
 
public class Solution {
    public List<List<Integer>> findSubsequences(int[] nums) {
        Set<List<Integer>> result = new HashSet<>();
        List<Integer> tempList = new ArrayList<>();
        findSequences(result, tempList, nums, 0);
        return result.stream().collect(Collectors.toList());
    }
 
    private void findSequences(Set<List<Integer>> result, List<Integer> tempList, int[] nums, int start) {
        if (tempList.size() > 1) {
            result.add(new ArrayList<>(tempList));
        }
        Arrays.stream(nums, start, nums.length).forEach(i -> {
            if (tempList.isEmpty() || tempList.get(tempList.size() - 1) <= nums[i]) {
                tempList.add(nums[i]);
                findSequences(result, tempList, nums, i + 1);
                tempList.remove(tempList.size() - 1);
            }
        });
    }
}