Class Solution
java.lang.Object
g0501_0600.s0509_fibonacci_number.Solution
509 - Fibonacci Number.<p>Easy</p>
<p>The <strong>Fibonacci numbers</strong> , commonly denoted <code>F(n)</code> form a sequence, called the <strong>Fibonacci sequence</strong> , such that each number is the sum of the two preceding ones, starting from <code>0</code> and <code>1</code>. That is,</p>
<p>F(0) = 0, F(1) = 1 F(n) = F(n - 1) + F(n - 2), for n > 1.</p>
<p>Given <code>n</code>, calculate <code>F(n)</code>.</p>
<p><strong>Example 1:</strong></p>
<p><strong>Input:</strong> n = 2</p>
<p><strong>Output:</strong> 1</p>
<p><strong>Explanation:</strong> F(2) = F(1) + F(0) = 1 + 0 = 1.</p>
<p><strong>Example 2:</strong></p>
<p><strong>Input:</strong> n = 3</p>
<p><strong>Output:</strong> 2</p>
<p><strong>Explanation:</strong> F(3) = F(2) + F(1) = 1 + 1 = 2.</p>
<p><strong>Example 3:</strong></p>
<p><strong>Input:</strong> n = 4</p>
<p><strong>Output:</strong> 3</p>
<p><strong>Explanation:</strong> F(4) = F(3) + F(2) = 2 + 1 = 3.</p>
<p><strong>Constraints:</strong></p>
<ul>
<li><code>0 <= n <= 30</code></li>
</ul>
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Solution
public Solution()
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fib
public int fib(int n)
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