[LeetCode Sync] Runtime - 47 ms (88.88%), Memory - 18 MB (83.01%)

Author: NinePiece2

Solutions/0387-first-unique-character-in-a-string/README.md

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+<p>Given a string <code>s</code>, find the <strong>first</strong> non-repeating character in it and return its index. If it <strong>does not</strong> exist, return <code>-1</code>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">s = &quot;leetcode&quot;</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">0</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<p>The character <code>&#39;l&#39;</code> at index 0 is the first character that does not occur at any other index.</p>
+</div>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">s = &quot;loveleetcode&quot;</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">2</span></p>
+</div>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">s = &quot;aabb&quot;</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">-1</span></p>
+</div>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>s</code> consists of only lowercase English letters.</li>
+</ul>

Solutions/0387-first-unique-character-in-a-string/solution.py

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+class Solution:
+    def firstUniqChar(self, s: str) -> int:
+        count = Counter(s)
+        for i, char in enumerate(s):
+            if count[char] == 1:
+                return i
+        return -1