From 77b431d27618a202d90b5bfc420b6686cbc66312 Mon Sep 17 00:00:00 2001
From: Jijie LIU <liujijieseason@gmail.com>
Date: Wed, 19 Oct 2022 22:20:01 +0200
Subject: [PATCH] =?UTF-8?q?Update=200541.=E5=8F=8D=E8=BD=AC=E5=AD=97?=
 =?UTF-8?q?=E7=AC=A6=E4=B8=B2II.md?=
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---
 problems/0541.反转字符串II.md | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/problems/0541.反转字符串II.md b/problems/0541.反转字符串II.md
index 02ad92a0..f38ac042 100644
--- a/problems/0541.反转字符串II.md
+++ b/problems/0541.反转字符串II.md
@@ -399,14 +399,17 @@ object Solution {
   }
 }
 ```
-版本二: 首先利用sliding每隔k个进行分割，随后转换为数组，再使用zipWithIndex添加每个数组的索引，紧接着利用map做变换，如果索引%2==0则说明需要翻转，否则原封不动，最后再转换为String
+版本二: 首先利用grouped每隔k个进行分割，再使用zipWithIndex添加每个数组的索引，紧接着利用map做变换，如果索引%2==0则说明需要翻转，否则原封不动，最后再转换为String
 ```scala
-object Solution {
+object SolutionFunc {
   def reverseStr(s: String, k: Int): String = {
-    s.sliding(k, k)
-      .toArray
-      .zipWithIndex
-      .map(v => if (v._2 % 2 == 0) v._1.reverse else v._1)
+    // s = "abcdefg", k = 2
+    s.grouped(k) // Iterator ["ab", "cd", "ef", "g"]
+      .zipWithIndex // Iterator [("ab", 0), ("cd", 1), ("ef", 2), ("g", 3)]
+      .map {
+        case (subStr, index) => 
+          if (index % 2 == 0) subStr.reverse else subStr
+      }
       .mkString
   }
 }