From 3d48e1bc7b105b5667d8b240f2d091a21630e85e Mon Sep 17 00:00:00 2001
From: huangge1199 <huangge1199@hotmail.com>
Date: Fri, 15 Oct 2021 13:50:27 +0800
Subject: [PATCH] =?UTF-8?q?509:=E6=96=90=E6=B3=A2=E9=82=A3=E5=A5=91?=
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 .../leetcode/editor/cn/FibonacciNumber.java   | 74 +++++++++++++++++++
 .../editor/cn/doc/content/FibonacciNumber.md  | 43 +++++++++++
 2 files changed, 117 insertions(+)
 create mode 100644 src/main/java/leetcode/editor/cn/FibonacciNumber.java
 create mode 100644 src/main/java/leetcode/editor/cn/doc/content/FibonacciNumber.md

diff --git a/src/main/java/leetcode/editor/cn/FibonacciNumber.java b/src/main/java/leetcode/editor/cn/FibonacciNumber.java
new file mode 100644
index 0000000..81316b7
--- /dev/null
+++ b/src/main/java/leetcode/editor/cn/FibonacciNumber.java
@@ -0,0 +1,74 @@
+//斐波那契数，通常用 F(n) 表示，形成的序列称为 斐波那契数列 。该数列由 0 和 1 开始，后面的每一项数字都是前面两项数字的和。也就是： 
+//
+// 
+//F(0) = 0，F(1) = 1
+//F(n) = F(n - 1) + F(n - 2)，其中 n > 1
+// 
+//
+// 给你 n ，请计算 F(n) 。 
+//
+// 
+//
+// 示例 1： 
+//
+// 
+//输入：2
+//输出：1
+//解释：F(2) = F(1) + F(0) = 1 + 0 = 1
+// 
+//
+// 示例 2： 
+//
+// 
+//输入：3
+//输出：2
+//解释：F(3) = F(2) + F(1) = 1 + 1 = 2
+// 
+//
+// 示例 3： 
+//
+// 
+//输入：4
+//输出：3
+//解释：F(4) = F(3) + F(2) = 2 + 1 = 3
+// 
+//
+// 
+//
+// 提示： 
+//
+// 
+// 0 <= n <= 30 
+// 
+// Related Topics 递归 记忆化搜索 数学 动态规划 👍 332 👎 0
+
+package leetcode.editor.cn;
+
+//509:斐波那契数
+class FibonacciNumber {
+    public static void main(String[] args) {
+        //测试代码
+        Solution solution = new FibonacciNumber().new Solution();
+    }
+
+    //力扣代码
+    //leetcode submit region begin(Prohibit modification and deletion)
+    class Solution {
+
+        public int fib(int n) {
+            if (n == 0 || n == 1) {
+                return n;
+            }
+            int n0 = 0;
+            int n1 = 1;
+            for (int i = 2; i <= n; i++) {
+                int temp = n0 + n1;
+                n0 = n1;
+                n1 = temp;
+            }
+            return n1;
+        }
+    }
+//leetcode submit region end(Prohibit modification and deletion)
+
+}
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diff --git a/src/main/java/leetcode/editor/cn/doc/content/FibonacciNumber.md b/src/main/java/leetcode/editor/cn/doc/content/FibonacciNumber.md
new file mode 100644
index 0000000..a290c5c
--- /dev/null
+++ b/src/main/java/leetcode/editor/cn/doc/content/FibonacciNumber.md
@@ -0,0 +1,43 @@
+<p><strong>斐波那契数</strong>，通常用 <code>F(n)</code> 表示，形成的序列称为 <strong>斐波那契数列</strong> 。该数列由 <code>0</code> 和 <code>1</code> 开始，后面的每一项数字都是前面两项数字的和。也就是：</p>
+
+<pre>
+F(0) = 0，F(1) = 1
+F(n) = F(n - 1) + F(n - 2)，其中 n > 1
+</pre>
+
+<p>给你 <code>n</code> ，请计算 <code>F(n)</code> 。</p>
+
+<p> </p>
+
+<p><strong>示例 1：</strong></p>
+
+<pre>
+<strong>输入：</strong>2
+<strong>输出：</strong>1
+<strong>解释：</strong>F(2) = F(1) + F(0) = 1 + 0 = 1
+</pre>
+
+<p><strong>示例 2：</strong></p>
+
+<pre>
+<strong>输入：</strong>3
+<strong>输出：</strong>2
+<strong>解释：</strong>F(3) = F(2) + F(1) = 1 + 1 = 2
+</pre>
+
+<p><strong>示例 3：</strong></p>
+
+<pre>
+<strong>输入：</strong>4
+<strong>输出：</strong>3
+<strong>解释：</strong>F(4) = F(3) + F(2) = 2 + 1 = 3
+</pre>
+
+<p> </p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li><code>0 <= n <= 30</code></li>
+</ul>
+<div><div>Related Topics</div><div><li>递归</li><li>记忆化搜索</li><li>数学</li><li>动态规划</li></div></div><br><div><li>👍 332</li><li>👎 0</li></div>
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