<p>Given an array of strings <code>strs</code>, return <em>the length of the <strong>longest uncommon subsequence</strong> between them</em>. If the longest uncommon subsequence does not exist, return <code>-1</code>.</p>

<p>An <strong>uncommon subsequence</strong> between an array of strings is a string that is a <strong>subsequence of one string but not the others</strong>.</p>

<p>A <strong>subsequence</strong> of a string <code>s</code> is a string that can be obtained after deleting any number of characters from <code>s</code>.</p>

<ul>
	<li>For example, <code>&quot;abc&quot;</code> is a subsequence of <code>&quot;aebdc&quot;</code> because you can delete the underlined characters in <code>&quot;a<u>e</u>b<u>d</u>c&quot;</code> to get <code>&quot;abc&quot;</code>. Other subsequences of <code>&quot;aebdc&quot;</code> include <code>&quot;aebdc&quot;</code>, <code>&quot;aeb&quot;</code>, and <code>&quot;&quot;</code> (empty string).</li>
</ul>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> strs = ["aba","cdc","eae"]
<strong>Output:</strong> 3
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> strs = ["aaa","aaa","aa"]
<strong>Output:</strong> -1
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>2 &lt;= strs.length &lt;= 50</code></li>
	<li><code>1 &lt;= strs[i].length &lt;= 10</code></li>
	<li><code>strs[i]</code> consists of lowercase English letters.</li>
</ul>

class Solution {
public:
    int findLUSlength(vector<string>& a) {
        int n = a.size();
        for (int len = 10; len >= 1; len--) {
            if (check(a, len)) return len;
        }
        return -1;
    }

    bool check(vector<string>&a, int len){
        int n = a.size();
        unordered_map<string,int> mp;
        for (auto x : a){
            unordered_set<string> st = get_subseq(x, len);
            for (auto str : st) mp[str]++;
        }
        for (auto x : mp) if (x.second == 1) return true;
        return false;
    }
    unordered_set<string> get_subseq(string x, int len){
        unordered_set<string> ans;
        string temp = "";
        helper(x,len,ans, 0, temp);
        return ans;
    }

    void helper(string x, int len, unordered_set<string>& st, int idx, string curr){
        int n = x.length();
        if (len == 0) st.insert(curr);
        else {
            for (int i = idx; i <n; i++){
                curr += x[i];
                helper(x,len-1, st, i+1, curr);
                curr.pop_back();
            }
        }

    }

};
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