parent
daf25d5e64
commit
07a359484b
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// File: linear_search.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package chapter_searching
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import (
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. "github.com/krahets/hello-algo/pkg"
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)
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// linerSearchArray 线性查找(数组)
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func linerSearchArray(nums []int, target int) int {
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// 遍历数组
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for i := 0; i < len(nums); i++ {
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if nums[i] == target {
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// 找到目标元素,返回其索引
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return i
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}
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}
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// 未找到目标元素,返回 -1
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return -1
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}
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// linerSearchLinkedList 线性查找(链表)
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func linerSearchLinkedList(node *ListNode, target int) *ListNode {
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// 遍历链表
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for node != nil {
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if node.Val == target {
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return node
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}
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node = node.Next
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}
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// 未找到目标元素,返回 nil
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return nil
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}
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@ -0,0 +1,24 @@
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// File: linear_search_test.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package chapter_searching
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import (
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. "github.com/krahets/hello-algo/pkg"
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"testing"
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)
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func TestLinearSearch(t *testing.T) {
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target := 3
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nums := []int{1, 5, 3, 2, 4, 7, 5, 9, 10, 8}
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// 在数组中执行线性查找
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index := linerSearchArray(nums, target)
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t.Log("目标元素 3 的索引 = ", index)
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// 在链表中执行线性查找
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head := ArrayToLinkedListLinkedList(nums)
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node := linerSearchLinkedList(head, target)
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t.Log("目标结点值 3 的对应结点对象为 ", node)
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}
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@ -0,0 +1,20 @@
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// File: binary_search_tree.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package chapter_tree
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import (
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. "github.com/krahets/hello-algo/pkg"
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"sort"
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)
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type BinarySearchTree struct {
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root *TreeNode
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}
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func NewBinarySearchTree(nums []int) *BinarySearchTree {
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// 排序数组
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sort.Ints(nums)
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return nil
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}
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// File: binary_tree.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package chapter_tree
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import (
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. "github.com/krahets/hello-algo/pkg"
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)
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type BinaryTree struct {
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root *TreeNode
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}
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func NewBinaryTree(node *TreeNode) *BinaryTree {
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return &BinaryTree{
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root: node,
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}
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}
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func (tree *BinaryTree) Print() {
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PrintTree(tree.root)
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}
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// File: binary_tree_test.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package chapter_tree
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import (
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. "github.com/krahets/hello-algo/pkg"
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"testing"
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)
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func TestBinaryTree(t *testing.T) {
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/* 初始化二叉树 */
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// 初始化节点
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n1 := NewTreeNode(1)
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n2 := NewTreeNode(2)
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n3 := NewTreeNode(3)
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n4 := NewTreeNode(4)
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n5 := NewTreeNode(5)
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tree := NewBinaryTree(n1)
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n1.Left = n2
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n1.Right = n3
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n2.Left = n4
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n2.Right = n5
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t.Log("初始化二叉树")
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tree.Print()
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/* 插入与删除结点 */
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p := NewTreeNode(0)
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n1.Left = p
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p.Left = n2
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t.Log("插入结点 P 后")
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tree.Print()
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// 删除结点
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n1.Left = n2
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t.Log("删除结点 P 后")
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tree.Print()
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}
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// File: list_node.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package pkg
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import (
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"fmt"
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"strconv"
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"strings"
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)
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// ListNode Definition for a singly-linked list node
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type ListNode struct {
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Next *ListNode
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Val int
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}
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// NewListNode Generate a list node with an val
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func NewListNode(v int) *ListNode {
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return &ListNode{
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Next: nil,
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Val: v,
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}
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}
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// ArrayToLinkedListLinkedList Generate a linked list with an array
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func ArrayToLinkedListLinkedList(arr []int) *ListNode {
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// dummy header of linked list
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dummy := NewListNode(0)
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node := dummy
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for _, val := range arr {
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node.Next = NewListNode(val)
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node = node.Next
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}
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return dummy.Next
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}
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// GetListNode Get a list node with specific value from a linked list
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func GetListNode(node *ListNode, val int) *ListNode {
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for node != nil && node.Val != val {
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node = node.Next
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}
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return node
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}
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// PrintLinkedList Print a linked list
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func PrintLinkedList(node *ListNode) {
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if node == nil {
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return
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}
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var builder strings.Builder
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for node.Next != nil {
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builder.WriteString(strconv.Itoa(node.Val) + " -> ")
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node = node.Next
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}
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builder.WriteString(strconv.Itoa(node.Val))
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fmt.Println(builder.String())
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}
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// File: list_node_test.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package pkg
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import "testing"
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func TestListNode(t *testing.T) {
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arr := []int{2, 3, 5, 6, 7}
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head := ArrayToLinkedListLinkedList(arr)
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PrintLinkedList(head)
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node := GetListNode(head, 5)
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t.Log("Find node: ", node.Val)
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}
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// File: tree_node.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package pkg
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import (
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"container/list"
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"fmt"
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)
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type TreeNode struct {
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Val int
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Left *TreeNode
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Right *TreeNode
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}
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func NewTreeNode(v int) *TreeNode {
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return &TreeNode{
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Left: nil,
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Right: nil,
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Val: v,
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}
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}
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// ArrayToTree Generate a binary tree with an array
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func ArrayToTree(arr []int) *TreeNode {
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if len(arr) <= 0 {
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return nil
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}
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root := NewTreeNode(arr[0])
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// Let container.list as queue
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queue := list.New()
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queue.PushBack(root)
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i := 1
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for queue.Len() > 0 {
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// poll
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node := queue.Remove(queue.Front()).(*TreeNode)
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if i < len(arr) {
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node.Left = NewTreeNode(arr[i])
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queue.PushBack(node.Left)
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i++
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}
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if i < len(arr) {
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node.Right = NewTreeNode(arr[i])
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queue.PushBack(node.Right)
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i++
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}
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}
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return root
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}
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// TreeToArray Serialize a binary tree to a list
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func TreeToArray(root *TreeNode) []int {
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if root == nil {
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return []int{}
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}
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arr := make([]int, 16)
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queue := list.New()
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queue.PushBack(root)
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for queue.Len() > 0 {
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node := queue.Remove(queue.Front()).(*TreeNode)
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if node != nil {
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arr = append(arr, node.Val)
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queue.PushBack(node.Left)
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queue.PushBack(node.Right)
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} else {
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arr = append(arr, -1)
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}
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}
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return arr
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}
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// PrintTree Print a binary tree
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func PrintTree(root *TreeNode) {
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PrintTreeHelper(root, nil, false)
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}
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// PrintTreeHelper Help to print a binary tree, hide more details
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// This tree printer is borrowed from TECHIE DELIGHT
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// https://www.techiedelight.com/c-program-print-binary-tree/
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func PrintTreeHelper(root *TreeNode, prev *trunk, isLeft bool) {
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if root == nil {
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return
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}
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prevStr := " "
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trunk := newTrunk(prev, prevStr)
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PrintTreeHelper(root.Right, trunk, true)
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if prev == nil {
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trunk.str = "———"
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} else if isLeft {
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trunk.str = "/———"
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prevStr = " |"
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} else {
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trunk.str = "\\———"
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prev.str = prevStr
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}
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showTrunk(trunk)
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fmt.Println(root.Val)
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if prev != nil {
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prev.str = prevStr
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}
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trunk.str = " |"
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PrintTreeHelper(root.Left, trunk, false)
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}
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// trunk Help to Print tree structure
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type trunk struct {
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prev *trunk
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str string
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}
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func newTrunk(prev *trunk, str string) *trunk {
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return &trunk{
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prev: prev,
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str: str,
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}
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}
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func showTrunk(t *trunk) {
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if t == nil {
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return
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}
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showTrunk(t.prev)
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fmt.Print(t.str)
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}
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// File: tree_node_test.go
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// Created Time: 2022-11-25
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// Author: Reanon (793584285@qq.com)
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package pkg
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import "testing"
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func TestTreeNode(t *testing.T) {
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arr := []int{2, 3, 5, 6, 7}
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node := ArrayToTree(arr)
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// print tree
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PrintTree(node)
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}
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Loading…
Reference in new issue