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book.leetcode/docs/hard/25.md

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+---
+weight: 25
+
+bookFlatSection: true
+
+BookToC: true
+
+title: "25. K 个一组翻转链表"
+---
+
+# 25. K 个一组翻转链表
+
+## 题目地址
+
++ [力扣](https://leetcode.cn/problems/reverse-nodes-in-k-group/)
++ [LeetCode](https://leetcode.com/problems/reverse-nodes-in-k-group/)
+
+## 解题思路
+
+## 具体实现
+
+{{< tabs "uniqueid" >}}
+
+{{< tab "Go" >}}
+
+```go
+package main
+
+import "fmt"
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+func reverseKGroup(head *ListNode, k int) *ListNode {
+	// 反转链表
+	reverse := func(head *ListNode) *ListNode {
+		if head == nil {
+			return nil
+		}
+
+		var (
+			prev, curr, next *ListNode
+		)
+		curr = head
+		for curr != nil {
+			next = curr.Next
+			curr.Next = prev
+
+			prev = curr
+			curr = next
+		}
+
+		return prev
+	}
+
+	dummy := &ListNode{}
+	var (
+		prev, end *ListNode
+	)
+
+	dummy.Next = head
+	prev = dummy
+	end = dummy
+
+	for end.Next != nil {
+		// 把 end 往后移动 k 个位置
+		for i := 0; i < k && end != nil; i++ {
+			end = end.Next
+		}
+		if end == nil {
+			break
+		}
+
+		start := prev.Next
+		next := end.Next
+		end.Next = nil
+
+		prev.Next = reverse(start)
+		start.Next = next
+
+		prev = start
+		end = start
+
+	}
+
+	return dummy.Next
+}
+
+func main() {
+	ret := reverseKGroup(&ListNode{
+		Val: 1,
+		Next: &ListNode{
+			Val: 2,
+			Next: &ListNode{
+				Val: 3,
+				Next: &ListNode{
+					Val: 4,
+					Next: &ListNode{
+						Val:  5,
+						Next: nil,
+					},
+				},
+			},
+		},
+	}, 2)
+
+	fmt.Println(ret)
+}
+
+```
+{{< /tab  >}}
+
+{{< /tabs  >}}
+
+## 参考
+
++ [链表中的节点每k个一组翻转](https://www.bilibili.com/video/BV1kg4y137UU)
++ [图解 K 个一组翻转链表](https://leetcode.cn/problems/reverse-nodes-in-k-group/solutions/10416/tu-jie-kge-yi-zu-fan-zhuan-lian-biao-by-user7208t/)
+