From eb0bbbf53c3b49acf1ce5c0648a12e5bfdcbaf01 Mon Sep 17 00:00:00 2001
From: ehlxr <ehlxr.me@gmail.com>
Date: Sun, 22 May 2022 23:54:36 +0800
Subject: [PATCH] update at 2022-05-22 23:54:36 by ehlxr

---
 go.mod         |  3 +++
 main.go        | 22 ++++++++++++++++++++++
 src/node.go    | 15 +++++++++++++++
 src/reverse.go | 43 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+)
 create mode 100644 go.mod
 create mode 100644 main.go
 create mode 100644 src/node.go
 create mode 100644 src/reverse.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..b621d96
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/ehlxr/leetcode-go
+
+go 1.18
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..6ff3b03
--- /dev/null
+++ b/main.go
@@ -0,0 +1,22 @@
+package main
+
+import (
+	"fmt"
+
+	. "github.com/ehlxr/leetcode-go/src"
+)
+
+func main() {
+	node5 := &Node{Value: 5, Next: nil}
+	node4 := &Node{Value: 4, Next: node5}
+	node3 := &Node{Value: 3, Next: node4}
+	node2 := &Node{Value: 2, Next: node3}
+	node1 := &Node{Value: 1, Next: node2}
+	root := &Node{Value: 0, Next: node1}
+
+	// fmt.Printf("%v\n", root)
+
+	// fmt.Printf("%v\n", Reverse(root))
+
+	fmt.Printf("%v\n", ReverseKGroup(root, 2))
+}
diff --git a/src/node.go b/src/node.go
new file mode 100644
index 0000000..2bc53bb
--- /dev/null
+++ b/src/node.go
@@ -0,0 +1,15 @@
+package src
+
+import "fmt"
+
+type Node struct {
+	Value int
+	Next  *Node
+}
+
+func (n *Node) String() string {
+	if n == nil {
+		return "nil"
+	}
+	return fmt.Sprintf("{Value:%d Next:%+v}", n.Value, *n.Next)
+}
diff --git a/src/reverse.go b/src/reverse.go
new file mode 100644
index 0000000..7641b5e
--- /dev/null
+++ b/src/reverse.go
@@ -0,0 +1,43 @@
+package src
+
+func Reverse(root *Node) *Node {
+	var pre, tmp *Node
+	cur := root
+	for cur != nil {
+		tmp = cur.Next
+		cur.Next = pre
+		pre = cur
+		cur = tmp
+
+	}
+	return pre
+}
+
+func ReverseKGroup(root *Node, k int) *Node {
+	if root == nil {
+		return root
+	}
+	n := root
+	for i := 0; i < k; i++ {
+		if n == nil {
+			break
+		}
+		n = n.Next
+	}
+	tmp := ReverseN(root, n)
+	root.Next = ReverseKGroup(n, k)
+	return tmp
+}
+
+func ReverseN(root *Node, n *Node) *Node {
+	var pre, tmp *Node
+	cur := root
+	for cur != n {
+		tmp = cur.Next
+		cur.Next = pre
+		pre = cur
+		cur = tmp
+
+	}
+	return pre
+}