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73 lines
1.4 KiB
HTML
73 lines
1.4 KiB
HTML
<p>Table: <code>MyNumbers</code></p>
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<pre>
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+-------------+------+
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| Column Name | Type |
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+-------------+------+
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| num | int |
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+-------------+------+
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This table may contain duplicates (In other words, there is no primary key for this table in SQL).
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Each row of this table contains an integer.
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</pre>
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<p> </p>
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<p>A <strong>single number</strong> is a number that appeared only once in the <code>MyNumbers</code> table.</p>
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<p>Find the largest <strong>single number</strong>. If there is no <strong>single number</strong>, report <code>null</code>.</p>
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<p>The result format is in the following example.</p>
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<ptable> </ptable>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<pre>
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<strong>Input:</strong>
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MyNumbers table:
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+-----+
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| num |
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+-----+
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| 8 |
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| 8 |
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| 3 |
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| 3 |
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| 1 |
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| 4 |
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| 5 |
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| 6 |
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+-----+
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<strong>Output:</strong>
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+-----+
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| num |
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+-----+
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| 6 |
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+-----+
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<strong>Explanation:</strong> The single numbers are 1, 4, 5, and 6.
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Since 6 is the largest single number, we return it.
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</pre>
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<p><strong class="example">Example 2:</strong></p>
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<pre>
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<strong>Input:</strong>
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MyNumbers table:
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+-----+
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| num |
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+-----+
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| 8 |
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| 8 |
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| 7 |
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| 7 |
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| 3 |
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| 3 |
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| 3 |
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+-----+
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<strong>Output:</strong>
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+------+
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| num |
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+------+
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| null |
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+------+
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<strong>Explanation:</strong> There are no single numbers in the input table so we return null.
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</pre>
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