二刷509

Author: diguage

docs/0509-fibonacci-number.adoc

@@ -44,10 +44,37 @@ Given `N`, calculate `F(N)`.
 
 0 ≤ `N` ≤ 30.
 
+== 思路分析
+
+动态规划
+
+image::images/0509-01.png[{image_attr}]
+
+image::images/0509-02.gif[{image_attr}]
 
 [[src-0509]]
+[tabs]
+====
+一刷::
++
+--
 [{java_src_attr}]
 ----
 include::{sourcedir}/_0509_FibonacciNumber.java[tag=answer]
 ----
+--
+
+二刷::
++
+--
+[{java_src_attr}]
+----
+include::{sourcedir}/_0509_FibonacciNumber_2.java[tag=answer]
+----
+--
+====
+
+== 参考资料
+
+. https://leetcode.cn/problems/fibonacci-number/solutions/2361746/509-fei-bo-na-qi-shu-dong-tai-gui-hua-qi-so8h/?envType=study-plan-v2&envId=selected-coding-interview[509. 斐波那契数 - 动态规划，清晰图解^]
 

docs/images/0509-01.png

@@ -818,6 +818,11 @@
 |{doc_base_url}/0104-maximum-depth-of-binary-tree.adoc[题解]
 |✅ 递归+回溯
 
+|{counter:codes}
+|{leetcode_base_url}/fibonacci-number/[509. Fibonacci Number^]
+|{doc_base_url}/0509-fibonacci-number.adoc[题解]
+|✅ 动态规划
+
 |===
 
 截止目前，本轮练习一共完成 {codes} 道题。

docs/images/0509-02.gif

@@ -9,10 +9,13 @@
  * @since 2020-04-25 22:06
  */
 public class _0509_FibonacciNumber {
-  // tag::answer[]
+    // tag::answer[]
     /**
      * Runtime: 0 ms, faster than 100.00% of Java online submissions for Fibonacci Number.
      * Memory Usage: 36.3 MB, less than 5.51% of Java online submissions for Fibonacci Number.
+     *
+     * @author D瓜哥 · https://www.diguage.com
+     * @since 2020-04-25 22:06
      */
     public int fib(int n) {
         if (n == 0) {
@@ -32,5 +35,5 @@ public int fib(int n) {
         }
         return Math.max(i1, i2);
     }
-  // end::answer[]
+    // end::answer[]
 }

logbook/202406.adoc

@@ -0,0 +1,20 @@
+package com.diguage.algo.leetcode;
+
+public class _0509_FibonacciNumber_2 {
+  // tag::answer[]
+
+  /**
+   * @author D瓜哥 · https://www.diguage.com
+   * @since 2024-09-21 17:30:28
+   */
+  public int fib(int n) {
+    int a = 0, b = 1, sum;
+    for (int i = 0; i < n; i++) {
+      sum = a + b;
+      a = b;
+      b = sum;
+    }
+    return a;
+  }
+  // end::answer[]
+}