<p>Given a string <code>s</code> and a string array <code>dictionary</code>, return <em>the longest string in the dictionary that can be formed by deleting some of the given string characters</em>. If there is more than one possible result, return the longest word with the smallest lexicographical order. If there is no possible result, return the empty string.</p>

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

<pre>
<strong>Input:</strong> s = &quot;abpcplea&quot;, dictionary = [&quot;ale&quot;,&quot;apple&quot;,&quot;monkey&quot;,&quot;plea&quot;]
<strong>Output:</strong> &quot;apple&quot;
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;abpcplea&quot;, dictionary = [&quot;a&quot;,&quot;b&quot;,&quot;c&quot;]
<strong>Output:</strong> &quot;a&quot;
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 1000</code></li>
	<li><code>1 &lt;= dictionary.length &lt;= 1000</code></li>
	<li><code>1 &lt;= dictionary[i].length &lt;= 1000</code></li>
	<li><code>s</code> and <code>dictionary[i]</code> consist of lowercase English letters.</li>
</ul>

class Solution {
public:
    string findLongestWord(string s, vector<string>& dictionary) {
        int n = s.size();
        vector<vector<int>> table(n, vector<int>(26));
        vector<int> cur_pos(26, -1);
        for (int i = n - 1; i >= 0; i--) {
            cur_pos[s[i] - 'a'] = i;
            table[i] = cur_pos;
        }
        auto is_sub_seq = [&table, &s](const string& str) {
            int n = s.size();
            int pos = -1;
            for (char c : str) {
                if (pos == n - 1) {
                    return false;
                }
                pos = table[pos + 1][c - 'a'];
                if (pos == -1) {
                    return false;
                }
            }
            return true;
        };
        sort(dictionary.begin(), dictionary.end(), [](const string& a, const string& b) {
            if (a.size() == b.size()) {
                return a < b;
            }
            return a.size() > b.size();
        });
        for (const string& str : dictionary) {
            if (is_sub_seq(str)) {
                return str;
            }
        }
        return "";
    }
};
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