二叉樹的操作

對於二叉樹的操作，做一個簡單的總結；
Tips：針對於任何樹的操作，首先需要判斷是不是空樹
樹的結構體：
int index = 0;

typedef struct BiTree
{
    int data;
    BiTree* lchild;
    BiTree* rchild;
}*Tree;

創建樹的操作：

void createBT(Tree &root,int data[])
{
    int value = data[index++];
    if(value == -1)
    {
        root = NULL;
    }
    else
    {
        root = new BiTree;
        root->data = value;
        createBT(root->lchild,data);
        createBT(root->rchild,data);
    }
}

計算結點個數：

int Count_Leaf(Tree &root)
{
    int count = 0;
    if(!root)
    {
        return count;
    }
    count = Count_Leaf(root->lchild)+Count_Leaf(root->rchild)+1;
    return count;
}

計算樹中葉子結點個數

int Count(Tree &root)
{
    if(!root)
        return 0;
    if(root->lchild == NULL && root->rchild == NULL)
        return 1;
    int numLeft = Count(root->lchild);
    int numRight = Count(root->rchild);
    return (numLeft+numRight);
}

二叉樹的深度：

int BT_depth(Tree &root)
{
    if(!root)
        return 0;
    int depth_left = BT_depth(root->lchild)+1;
    int depth_right = BT_depth(root->rchild)+1;
    return depth_left>depth_right?depth_left:depth_right;
}

二叉樹的bfs遍歷：

void Level(Tree &root)
{
    cout << "二叉樹的層次遍歷" << endl;
    queue<BiTree*> que;
    if(!root)
        return;
    que.push(root);
    while(!que.empty())
    {
        root = que.front();
        que.pop();
        cout << root->data << " ";
        if(root->lchild)
            que.push(root->lchild);
        if(root->rchild)
            que.push(root->rchild);
    }
}

二叉樹的dfs遍歷：

void dfs(Tree &root)
{
    stack<BiTree*> s;
    if(!root)
        return;
    s.push(root);
    while(!s.empty())
    {
        root = s.top();
        cout << root->data << " ";
        s.pop();
        if(root->rchild)
            s.push(root->rchild);
        if(root->lchild)
            s.push(root->lchild);
    }
}

二叉樹第K層結點數：

int K_level(Tree &root,int k)
{
    if(!root || k<1)
        return 0;
    if(k == 1)
        return 1;
    int numLeft = K_level(root->lchild,k-1);
    int numright = K_level(root->rchild,k-1);
    return (numLeft+numright);
}

判斷倆個二叉樹是否是一樣的？

bool Same_BT(Tree &root1,Tree &root2)
{
    if(!root1 && !root2)
        return true;
    if(!root1 || !root2)
        return false;
    bool leftSame = Same_BT(root1->lchild,root2->lchild);
    bool rightSame = Same_BT(root1->rchild,root2->rchild);
    return (leftSame&&rightSame);
}

二叉樹的鏡像：

BiTree* Mirror(Tree &root)
{
    if(!root)
        return NULL;
    BiTree* left = Mirror(root->lchild);
    BiTree* right = Mirror(root->rchild);
    root->lchild = right;
    root->rchild = left;
    return root;
}

是否是平衡二叉樹：

bool isAVL(Tree &root,int &height)
{
    if(!root)
    {
        height = 0;
        return true;
    }
    int heightLeft;
    bool left = isAVL(root->lchild,heightLeft);
    int heightRight;
    bool right = isAVL(root->rchild,heightRight);
    if(left && right && abs(heightLeft-heightRight)<=1)
    {
        height = max(heightLeft,heightRight)+1;
        return true;
    }
    else
    {
         height = max(heightLeft,heightRight)+1;
         return false;
    }
}

操作的main（）函數：

int main()
{
    int data[] = {8,6,4,-1,-1,7,-1,-1,10,9,-1,-1,11,-1,-1};
    int data1[] = {8,6,4,-1,-1,7,-1,-1,10,9,-1,-1,11,-1,-1};
    Tree tree;
    Tree tree1;
    createBT(tree,data);
    /*
    //int height;
    if(isAVL(tree,height))
    {
        cout << "isAVL" << endl;
    }*/
    createBT(tree1,data1);

    if(Same_BT(tree,tree1))
    {
        cout<< "這倆二叉樹是一樣的" << endl;
    }
    else
    {
        cout << "這倆二叉樹是不一樣的" << endl;
    }
    //cout << "二叉樹的葉子節點個數" << endl;
    //cout<<Count_Leaf(tree);
    //cout<<Count(tree)<<endl;
    //cout<<BT_depth(tree);*/
    //Level(tree);

    //cout << endl;
    //Mirror(tree);
    //Level(tree);
    //cout<< endl;
   // dfs(tree);
   //cout<< K_level(tree,3)<<endl;
    return 0;
}