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39 lines
1.3 KiB
HTML
39 lines
1.3 KiB
HTML
<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>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">s = "leetcode"</span></p>
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<p><strong>Output:</strong> <span class="example-io">0</span></p>
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<p><strong>Explanation:</strong></p>
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<p>The character <code>'l'</code> at index 0 is the first character that does not occur at any other index.</p>
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</div>
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<p><strong class="example">Example 2:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">s = "loveleetcode"</span></p>
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<p><strong>Output:</strong> <span class="example-io">2</span></p>
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</div>
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<p><strong class="example">Example 3:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">s = "aabb"</span></p>
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<p><strong>Output:</strong> <span class="example-io">-1</span></p>
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</div>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>1 <= s.length <= 10<sup>5</sup></code></li>
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<li><code>s</code> consists of only lowercase English letters.</li>
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</ul>
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