update circular

link/circular.go

@@ -0,0 +1,55 @@
+package link
+
+import (
+	"errors"
+	"fmt"
+)
+
+type CirLink struct {
+	Val  interface{}
+	Next *CirLink
+}
+
+func NewCirLink() *CirLink {
+	return &CirLink{}
+}
+
+// 插入值
+func (c *CirLink) AppendCirLink(data interface{}) {
+	if c.Next == nil {
+		c.Next = &CirLink{data, c}
+		return
+	}
+	node := c.Next
+	if node.Next.Val == nil {
+		node.Next = &CirLink{data, node.Next}
+		return
+	}
+	c.Next.AppendCirLink(data)
+}
+
+// 删除值
+
+func (c *CirLink) DeleteCirLink(data interface{}) error {
+	node := c.Next
+	if node.Val == data {
+		c.Next = node.Next
+		return nil
+	}
+	if node.Next.Val == nil {
+		err := errors.New("未找到对应值")
+		return err
+	}
+	c.Next.DeleteCirLink(data)
+	return nil
+}
+
+// 遍历数值
+
+func (c *CirLink) TraversalCirLink() {
+	node := c.Next
+	fmt.Printf("遍历信息为:val=%d\n", node.Val)
+	if node.Next.Val != nil {
+		node.TraversalCirLink()
+	}
+}

link/circular_test.go

@@ -0,0 +1,19 @@
+package link
+
+import (
+	"testing"
+)
+
+func TestCirCular(t *testing.T) {
+	clink := NewCirLink()
+	// 5,7,10,13,100,3000
+	clink.AppendCirLink(5)
+	clink.AppendCirLink(7)
+	clink.AppendCirLink(10)
+	clink.AppendCirLink(13)
+	clink.AppendCirLink(100)
+	clink.AppendCirLink(3000)
+	clink.TraversalCirLink()
+	clink.DeleteCirLink(13)
+	clink.TraversalCirLink()
+}

link/leet142.go

@@ -0,0 +1,17 @@
+package link
+
+func detectCycle(head *ListNode) *ListNode {
+	// 判断只有第一个值的时候
+	if head == nil || head.Next == nil {
+		return nil
+	}
+	// 循环1
+	node := head
+	for node.Next != nil {
+		if node.Next == head {
+			// 证明是个环
+			return head
+		}
+	}
+	return detectCycle(head.Next)
+}

link/leet142_test.go

@@ -0,0 +1,18 @@
+package link
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestDetectCycle(t *testing.T) {
+	// 例子3
+	node := NewListNode(1)
+	res := detectCycle(node)
+	fmt.Println(res)
+	// 例子2
+	node.addNode(2)
+	node.Next = node
+	res = detectCycle(node)
+	fmt.Println(res)
+}