Go语言二叉树定义及遍历算法实现

// binary_tree 二叉树
package Algorithm

import (
    "reflect"
)

// 二叉树定义
type BinaryTree struct {
    Data   interface{}
    Lchild *BinaryTree
    Rchild *BinaryTree
}

// 构造方法
func NewBinaryTree(data interface{}) *BinaryTree {
    return &BinaryTree{Data: data}
}

// 先序遍历
func (bt *BinaryTree) PreOrder() []interface{} {
    t := bt
    stack := NewStack(reflect.TypeOf(bt))
    res := make([]interface{}, 0)
    for t != nil || !stack.Empty() {
        for t != nil {
            res = append(res, t.Data)
            stack.Push(t)
            t = t.Lchild
        }
        if !stack.Empty() {
            v, _ := stack.Pop()
            t = v.(*BinaryTree)
            t = t.Rchild
        }
    }
    return res
}

// 中序遍历
func (bt *BinaryTree) InOrder() []interface{} {
    t := bt
    stack := NewStack(reflect.TypeOf(bt))
    res := make([]interface{}, 0)
    for t != nil || !stack.Empty() {
        for t != nil {
            stack.Push(t)
            t = t.Lchild
        }
        if !stack.Empty() {
            v, _ := stack.Pop()
            t = v.(*BinaryTree)
            res = append(res, t.Data)
            t = t.Rchild
        }
    }
    return res
}

// 后续遍历
func (bt *BinaryTree) PostOrder() []interface{} {
    t := bt
    stack := NewStack(reflect.TypeOf(bt))
    s := NewStack(reflect.TypeOf(true))
    res := make([]interface{}, 0)
    for t != nil || !stack.Empty() {
        for t != nil {
            stack.Push(t)
            s.Push(false)
            t = t.Lchild
        }
        for flag, _ := s.Top(); !stack.Empty() && flag.(bool); {
            s.Pop()
            v, _ := stack.Pop()
            res = append(res, v.(*BinaryTree).Data)
            flag, _ = s.Top()
        }
        if !stack.Empty() {
            s.Pop()
            s.Push(true)
            v, _ := stack.Top()
            t = v.(*BinaryTree)
            t = t.Rchild
        }
    }
    return res
}