<p>Given an integer array <code>nums</code>, return <em>all the different possible non-decreasing subsequences of the given array with at least two elements</em>. You may return the answer in <strong>any order</strong>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [4,6,7,7]
<strong>Output:</strong> [[4,6],[4,6,7],[4,6,7,7],[4,7],[4,7,7],[6,7],[6,7,7],[7,7]]
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [4,4,3,2,1]
<strong>Output:</strong> [[4,4]]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 15</code></li>
	<li><code>-100 &lt;= nums[i] &lt;= 100</code></li>
</ul>

class Solution {
    void computeRes(int idx, vector<int> &nums, vector<int> cur, 
                    vector<vector<int>> &result, set<vector<int>> &st) {
        if(idx == nums.size()) {
            if(cur.size() > 1 && st.count(cur) == 0) {
                result.push_back(cur);
                st.insert(cur);
            }
            return;
        }

        // notTake
        computeRes(idx + 1, nums, cur, result, st);

        // take
        if(cur.empty() || cur.back() <= nums[idx]){
            cur.push_back(nums[idx]);
            computeRes(idx+1, nums, cur, result, st);
        }
    }
public:
    vector<vector<int>> findSubsequences(vector<int>& nums) {
        vector<vector<int>> result;
        vector<int> cur;
        set<vector<int>> st;
        computeRes(0, nums, cur, result, st);

        return result;
    }
};
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