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30 lines
1.4 KiB
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30 lines
1.4 KiB
HTML
<p>Given the <strong>API</strong> <code>rand7()</code> that generates a uniform random integer in the range <code>[1, 7]</code>, write a function <code>rand10()</code> that generates a uniform random integer in the range <code>[1, 10]</code>. You can only call the API <code>rand7()</code>, and you shouldn't call any other API. Please <strong>do not</strong> use a language's built-in random API.</p>
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<p>Each test case will have one <strong>internal</strong> argument <code>n</code>, the number of times that your implemented function <code>rand10()</code> will be called while testing. Note that this is <strong>not an argument</strong> passed to <code>rand10()</code>.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre><strong>Input:</strong> n = 1
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<strong>Output:</strong> [2]
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</pre><p><strong>Example 2:</strong></p>
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<pre><strong>Input:</strong> n = 2
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<strong>Output:</strong> [2,8]
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</pre><p><strong>Example 3:</strong></p>
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<pre><strong>Input:</strong> n = 3
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<strong>Output:</strong> [3,8,10]
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</pre>
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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 <= n <= 10<sup>5</sup></code></li>
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</ul>
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<p> </p>
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<p><strong>Follow up:</strong></p>
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<ul>
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<li>What is the <a href="https://en.wikipedia.org/wiki/Expected_value" target="_blank">expected value</a> for the number of calls to <code>rand7()</code> function?</li>
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<li>Could you minimize the number of calls to <code>rand7()</code>?</li>
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</ul>
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