From e5fca8a7a9b5684cfbca520ceb34e91051288219 Mon Sep 17 00:00:00 2001
From: VicRen <vic.ren@me.com>
Date: Fri, 11 Dec 2020 10:19:38 +0800
Subject: [PATCH] 20201211

---
 20201211/main.go      | 47 +++++++++++++++++++++++++++++++++++++++++++
 20201211/main_test.go | 39 +++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 20201211/main.go
 create mode 100644 20201211/main_test.go

diff --git a/20201211/main.go b/20201211/main.go
new file mode 100644
index 0000000..421d189
--- /dev/null
+++ b/20201211/main.go
@@ -0,0 +1,47 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+//给定一个字符串 s 和一个整数 k，你需要对从字符串开头算起的每隔 2k 个字符的前 k 个字符进行反转。
+//
+//如果剩余字符少于 k 个，则将剩余字符全部反转。
+//如果剩余字符小于 2k 但大于或等于 k 个，则反转前 k 个字符，其余字符保持原样。
+
+func main() {
+
+}
+
+func process(k int, s string) string {
+	sb := strings.Builder{}
+	l := 0
+	r := 2 * k
+	for {
+		fmt.Println(l, r)
+		if r > len(s) {
+			if l > len(s) {
+				sb.WriteString(s[r-2*k:])
+			} else {
+				sb.WriteString(reverse(s[l : l+k]))
+				sb.WriteString(s[l+k:])
+			}
+			break
+		}
+		sb.WriteString(reverse(s[l : l+k]))
+		sb.WriteString(s[l+k : r])
+		l += 2 * k
+		r += 2 * k
+	}
+	return sb.String()
+}
+
+func reverse(s string) string {
+	src := []rune(s)
+	l := len(src)
+	for i := 0; i < l/2; i++ {
+		src[i], src[l-i-1] = src[l-i-1], src[i]
+	}
+	return string(src)
+}
diff --git a/20201211/main_test.go b/20201211/main_test.go
new file mode 100644
index 0000000..bbe2f9b
--- /dev/null
+++ b/20201211/main_test.go
@@ -0,0 +1,39 @@
+package main
+
+import "testing"
+
+func Test_process(t *testing.T) {
+	type args struct {
+		k int
+		s string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			"test1",
+			args{
+				2,
+				"abcdefg",
+			},
+			"bacdfeg",
+		},
+		{
+			"test2",
+			args{
+				4,
+				"abcdefg",
+			},
+			"dcbaefg",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := process(tt.args.k, tt.args.s); got != tt.want {
+				t.Errorf("process() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}