<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 {
public:
    void fun(int i, vector<int> &nums, vector<int> &ans,set<vector<int>> &set){
        if(i==nums.size()){
            if(ans.size()>1) set.insert(ans);
            return;
        }
        if(ans.empty() || ans.back()<=nums[i]){
            ans.push_back(nums[i]);
            int j = i+1;
            fun(j,nums,ans,set);
            ans.pop_back();
        }
        int j = i+1;
        while(j<nums.size()&&nums[j]==nums[i]) j++;
        fun(j,nums,ans,set);
    }
    vector<vector<int>> findSubsequences(vector<int>& nums) {
        vector<int> ans;
        set<vector<int>> set;
        fun(0,nums,ans,set);
        return vector<vector<int>>(set.begin(),set.end());
    }
};
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