491.cpp

// dfs.cpp
class Solution {
  set<vector<int>> myset;

public:
  vector<vector<int>> findSubsequences(vector<int> &nums) {
    dfs(nums, vector<int>(), 0);
    vector<vector<int>> res(myset.begin(), myset.end());
    return res;
  }
  void dfs(vector<int> &nums, vector<int> arr, int i) {
    if (i == nums.size())
      return;
    dfs(nums, arr, i + 1);
    if (arr.size() == 0 || nums[i] >= arr.back()) {
      arr.push_back(nums[i]);
      if (arr.size() > 1 && myset.find(arr) == myset.end())
        myset.insert(arr);
      dfs(nums, arr, i + 1);
    }
  }
};