Find the Difference
<p>You are given two strings <code>s</code> and <code>t</code>.</p>

<p>String <code>t</code> is generated by random shuffling string <code>s</code> and then add one more letter at a random position.</p>

<p>Return the letter that was added to <code>t</code>.</p>

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

<pre>
<strong>Input:</strong> s = &quot;abcd&quot;, t = &quot;abcde&quot;
<strong>Output:</strong> &quot;e&quot;
<strong>Explanation:</strong> &#39;e&#39; is the letter that was added.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;&quot;, t = &quot;y&quot;
<strong>Output:</strong> &quot;y&quot;
</pre>

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

<ul>
	<li><code>0 &lt;= s.length &lt;= 1000</code></li>
	<li><code>t.length == s.length + 1</code></li>
	<li><code>s</code> and <code>t</code> consist of lowercase English letters.</li>
</ul>
Bit Manipulation; Hash Table; String; Sorting
char findTheDifference(char* s, char* t) {
    int n = strlen(s);
    int cnt[26] = {0};
    for (int i = 0; i < n; i++) {
        cnt[s[i] - 'a']++;
        cnt[t[i] - 'a']--;
    }
    cnt[t[n] - 'a']--;
    for (int i = 0;; i++) {
        if (cnt[i]) {
            return 'a' + i;
        }
    }
}