ツリーを巡ってまとめる

1.再帰遍歴

struct bnode
{
    char data;
    struct bnode *lchild,*rchild;
};
typedef bnode* bitre;

//      
void PreOrderRec(bitre root)
{
    cout << root->data;
    PreOrderRec(root->lchild);
    PreOrderRec(root->rchild);
}

//      
void InOrderRec(bitre root)
{
    PreOrderRec(root->lchild);
    cout << root->data;
    PreOrderRec(root->rchild);
}

//      
void InOrderRec(bitre root)
{
    PreOrderRec(root->lchild);
    PreOrderRec(root->rchild);
    cout << root->data;
}

2.再帰的でない遍歴

struct bnode
{
    char data;
    struct bnode *lchild,*rchild;
};
typedef bnode* bitre;

struct TreeNode
{
    bitre node;
    bool vis;

    TreeNode(bitre node, bool vis)
    {
        this->node = node;
        this->vis = vis;
    }
};

//    ： ->   ->   
void PreOrder(TreeNode root)
{
    stack stk;
    stk.push(root);

    while (!stk.empty())
    {
        TreeNode curNode = stk.top();
        stk.pop();
        if (!curNode.node)
        {
            continue;
        }
        if (curNode.vis)
        {
            cout << curNode.node->data;
        }
        else
        {
            stk.push(TreeNode(curNode.node->rchild, false));
            stk.push(TreeNode(curNode.node->lchild, false));
            stk.push(TreeNode(curNode.node, true));
        }
    }
}

//    ：   -> ->   
void InOrder(TreeNode root)
{
    stack stk;
    stk.push(root);

    while (!stk.empty())
    {
        TreeNode curNode = stk.top();
        stk.pop();
        if (!curNode.node)
        {
            continue;
        }
        if (curNode.vis)
        {
            cout << curNode.node->data;
        }
        else
        {
            stk.push(TreeNode(curNode.node->rchild, false));
            stk.push(TreeNode(curNode.node, true));
            stk.push(TreeNode(curNode.node->lchild, false));
        }
    }
}

//    :    ->   -> 
void PostOrder(TreeNode root)
{
    stack stk;
    stk.push(root);

    while (!stk.empty())
    {
        TreeNode curNode = stk.top();
        stk.pop();
        if (!curNode.node)
        {
            continue;
        }
        if (curNode.vis)
        {
            cout << curNode.node->data;
        }
        else
        {
            stk.push(TreeNode(curNode.node, true));
            stk.push(TreeNode(curNode.node->rchild, false));
            stk.push(TreeNode(curNode.node->lchild, false));
        }
    }
}