<p>Given a string&nbsp;<code>s</code><var>,</var>&nbsp;return <em>the maximum&nbsp;number of unique substrings that the given string can be split into</em>.</p>

<p>You can split string&nbsp;<code>s</code> into any list of&nbsp;<strong>non-empty substrings</strong>, where the concatenation of the substrings forms the original string.&nbsp;However, you must split the substrings such that all of them are <strong>unique</strong>.</p>

<p>A <strong>substring</strong> is a contiguous sequence of characters within a string.</p>

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

<pre>
<strong>Input:</strong> s = &quot;ababccc&quot;
<strong>Output:</strong> 5
<strong>Explanation</strong>: One way to split maximally is [&#39;a&#39;, &#39;b&#39;, &#39;ab&#39;, &#39;c&#39;, &#39;cc&#39;]. Splitting like [&#39;a&#39;, &#39;b&#39;, &#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;cc&#39;] is not valid as you have &#39;a&#39; and &#39;b&#39; multiple times.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;aba&quot;
<strong>Output:</strong> 2
<strong>Explanation</strong>: One way to split maximally is [&#39;a&#39;, &#39;ba&#39;].
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;aa&quot;
<strong>Output:</strong> 1
<strong>Explanation</strong>: It is impossible to split the string any further.
</pre>

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

<ul>
	<li>
	<p><code>1 &lt;= s.length&nbsp;&lt;= 16</code></p>
	</li>
	<li>
	<p><code>s</code> contains&nbsp;only lower case English letters.</p>
	</li>
</ul>

class Solution {
public:
    void solve(string s, int ind, unordered_set<string> &st, int &ans)
    {
        if(ind == s.size())
        {
            int n = st.size();
            ans = max(ans, n);
            return;
        }
        string curr = "";
        for(int i=ind;i<=s.size();i++)
        {
            curr+=s[i];
            if(st.find(curr) == st.end())
            {
                st.insert(curr);
                solve(s, i+1, st, ans);
                st.erase(curr);
            }            
        }

    }
    int maxUniqueSplit(string s) {
        unordered_set<string> st;
        // string curr = "";
        // for(int i=0;i<s.size();i++)
        // {
        //     curr += s[i];
        //     if(st.find(curr) == st.end())
        //     {
        //         st.insert(curr);
        //         curr="";
        //     }
        // }
        // // for(auto val : st)
        // // {
        // //     cout<<val<<endl;
        // // }
        // // if(curr != "")
        // //     return st.size()+1;
        // return st.size();
        int ans = 0;
        solve(s, 0, st, ans);
        return ans;
    }
};
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