leetcode-problemset/leetcode-cn/problem (English)/判定字符是否唯一(English) [is-unique-lcci].html

<p>Implement an algorithm to determine if a string has all unique characters. What if you cannot use additional data structures?</p>



<p><strong>Example 1:</strong></p>



<pre>

<strong>Input: </strong><code>s</code> = &quot;leetcode&quot;

<strong>Output: </strong>false

</pre>



<p><strong>Example 2:</strong></p>



<pre>

<strong>Input: </strong><code>s</code> = &quot;abc&quot;

<strong>Output: </strong>true

</pre>



<p>&nbsp;</p>



<p><strong>Note:</strong></p>



<ul>

	<li><code>0 &lt;= len(s) &lt;= 100 </code></li>

</ul>