<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 {
  unordered_map<string, int> mp;
  unordered_set<string> st;
  
  void generateSubsequences(string& s, int idx, string p) {
    if (idx == s.length()) {
      st.insert(p);
      return;
    }
    generateSubsequences(s, idx+1, p + s[idx]);
    generateSubsequences(s, idx+1, p);
  }
  
public:
    int findLUSlength(vector<string>& strs) {
      for (int i = 0; i < strs.size(); i++) {
        generateSubsequences(strs[i], 0, "");
        for (auto it = st.begin(); it != st.end(); it++) {
          mp[*it]++;
        }
        st.clear();
      }

      int ans = -1;
      for (auto it = mp.begin(); it != mp.end(); it++) {
        if (it->second == 1) {
          int len = (it->first).length();
          ans = max(ans, len);
        }
      }
      return ans;
    }
};
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