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31 lines
868 B
HTML
31 lines
868 B
HTML
<p>The Tribonacci sequence T<sub>n</sub> is defined as follows: </p>
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<p>T<sub>0</sub> = 0, T<sub>1</sub> = 1, T<sub>2</sub> = 1, and T<sub>n+3</sub> = T<sub>n</sub> + T<sub>n+1</sub> + T<sub>n+2</sub> for n >= 0.</p>
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<p>Given <code>n</code>, return the value of T<sub>n</sub>.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> n = 4
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<strong>Output:</strong> 4
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<strong>Explanation:</strong>
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T_3 = 0 + 1 + 1 = 2
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T_4 = 1 + 1 + 2 = 4
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</pre>
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<p><strong>Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> n = 25
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<strong>Output:</strong> 1389537
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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>0 <= n <= 37</code></li>
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<li>The answer is guaranteed to fit within a 32-bit integer, ie. <code>answer <= 2^31 - 1</code>.</li>
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</ul> |