C 二叉树的一些操作

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今天不开森，自行车在楼下被偷了

二叉树的创建

//先序创建二叉树
void CreatBinarTreeNode(BiThrTree *T){
    char c;
    scanf("%c", &c);
    //输出空格就是没有了
    if ( ' ' == c ){
        *T = NULL;
    }else {
        *T = (BiThrNode *)malloc(sizeof(BiThrNode));
        (*T)->data = c;
        //创建完跟节点创建下面左右子树
        CreatBinarTreeNode(&(*T)->LeftTreeNode);
        CreatBinarTreeNode(&(*T)->RightTreeNode);
    }
}

二叉树的先序遍历

//先序遍历，完全是按照递归的方式来走，很C
void putout1(BiThrTree T){
    if(T)
    {
        printf("%c ", T->data);
        putout1(T->LeftTreeNode);
        putout1(T->RightTreeNode);
    }
}

二叉树的中序遍历

//中序遍历
void putout2(BiThrTree T){
    if(T)
    {
        putout2(T->LeftTreeNode);
        printf("%c ", T->data);
        putout2(T->RightTreeNode);
    }
}

二叉树的后序遍历

//后序遍历
void putout3(BiThrTree T){
    if(T)
    {
        putout3(T->LeftTreeNode);
        putout3(T->RightTreeNode);
        printf("%c ", T->data);
    }
}

看看有多少个叶子节点（度为0的节点）

//叶子节点
int Leafnum(BiThrTree T){
	//节点啥也没有就返回0
    if(!T)
        return 0;
    //叶子节点就是最下面的，就是左右节点均无的
    else if (!T->LeftTreeNode && !T->RightTreeNode)
        return 1;
    //按照递归来找就可以了
    else
        return Leafnum(T->LeftTreeNode) + Leafnum(T->RightTreeNode);
    return -1;
}

总共有多少个节点

//总节点
int nodeNum(BiThrTree T){
    if(!T)
        return 0;
    //只要走过有东西那就加1
    else
        return 1 + nodeNum(T->LeftTreeNode)+nodeNum(T->RightTreeNode);
    return -1;
}

二叉树的高度

//二叉树的高度
int heightBitree(BiThrTree T){
	//空节点肯定是0
    if(!T)
        return 0;
    //因为二叉树的高度就是左右树那个最长的那个
    //所以逆向来的话就是比较子节点的高度，哪个高要哪个
    else
    {
    	int Lheight = heightBitree(T->LeftTreeNode);
    	int Rheight = heightBitree(T->RightTreeNode);
    	return Lheight > Rheight ? Lheight+1 : Rheight+1;
    }
        
    return -1;
}

度为1的节点个数

//度为1的节点个数
int nodeOnenume(BiThrTree T){
    if(!T)
        return 0;
    //只要符合条件就加一,并且看看下面还有木有
    else if((T->LeftTreeNode && !T->RightTreeNode) || (!T->LeftTreeNode && T->RightTreeNode))
        return 1 + nodeOnenume(T->LeftTreeNode) + nodeOnenume(T->RightTreeNode);
    //继续递归
    else
        return nodeOnenume(T->LeftTreeNode) + nodeOnenume(T->RightTreeNode);
    return 0;
}

度为2的节点个数

//度为2的节点个数
int nodeTwonume(BiThrTree T){
    if(!T)
        return 0;
    //符合条件接着往下找
    else if(T->LeftTreeNode && T->RightTreeNode)
        return 1 + nodeTwonume(T->LeftTreeNode) + nodeTwonume(T->RightTreeNode);
    //度为1的结点的话，就看看它的子节点里有木有
    else
    	return nodeOnenume(T->LeftTreeNode) + nodeOnenume(T->RightTreeNode);
    return -1;
}

交换左右子树

//交换左右子树
void exchangeTree(BiThrTree *T){
    if(*T){
    	//这里就将两个大的子树就换了
        BiThrTree temp = (*T)->LeftTreeNode;
        (*T)->LeftTreeNode = (*T)->RightTreeNode;
        (*T)->RightTreeNode = temp;
        //还是递归，子树的规模会缩小，也会越细节
        exchangeTree(&(*T)->LeftTreeNode);
        exchangeTree(&(*T)->RightTreeNode);
    }
}

完整代码

//
//  main.c
//  二叉树的若干操作
//
//  Created by 赫凯 on 2018/10/26.
//  Copyright © 2018 赫凯. All rights reserved.
//
#include <stdlib.h>
#include <stdio.h>

typedef int ElementType;

typedef struct BinaryTreeNode{
    ElementType data;
    struct BinaryTreeNode *LeftTreeNode;
    struct BinaryTreeNode *RightTreeNode;
}BiThrNode, *BiThrTree;

//先序创建二叉树
void CreatBinarTreeNode(BiThrTree *T){
    char c;
    scanf("%c", &c);
    
    if ( ' ' == c ){
        *T = NULL;
    }else {
        *T = (BiThrNode *)malloc(sizeof(BiThrNode));
        (*T)->data = c;
        
        CreatBinarTreeNode(&(*T)->LeftTreeNode);
        CreatBinarTreeNode(&(*T)->RightTreeNode);
    }
}

//先序遍历
void putout1(BiThrTree T){
    if(T)
    {
        printf("%c ", T->data);
        putout1(T->LeftTreeNode);
        putout1(T->RightTreeNode);
    }
}

//中序遍历
void putout2(BiThrTree T){
    if(T)
    {
        putout2(T->LeftTreeNode);
        printf("%c ", T->data);
        putout2(T->RightTreeNode);
    }
}
//后序遍历
void putout3(BiThrTree T){
    if(T)
    {
        putout3(T->LeftTreeNode);
        putout3(T->RightTreeNode);
        printf("%c ", T->data);
    }
}

void putout(BiThrTree T){
    printf("\n先序:");
    putout1(T);
    printf("\n中序:");
    putout2(T);
    printf("\n后序:");
    putout3(T);
}
//叶子节点
int Leafnum(BiThrTree T){
    if(!T)
        return 0;
    else if (!T->LeftTreeNode && !T->RightTreeNode)
        return 1;
    else
        return Leafnum(T->LeftTreeNode)+Leafnum(T->RightTreeNode);
    return -1;
}
//总节点
int nodeNum(BiThrTree T){
    if(!T)
        return 0;
    else
        return 1+nodeNum(T->LeftTreeNode)+nodeNum(T->RightTreeNode);
    return -1;
}
//二叉树的高度
int heightBitree(BiThrTree T){
    if(!T)
        return 0;
    else
        return heightBitree(T->LeftTreeNode)>heightBitree(T->RightTreeNode)?heightBitree(T->LeftTreeNode)+1:heightBitree(T->RightTreeNode)+1;
    return -1;
}
//度为1的节点个数
int nodeOnenume(BiThrTree T){
    if(!T)
        return 0;
    else if((T->LeftTreeNode && !T->RightTreeNode) || (!T->LeftTreeNode && T->RightTreeNode))
        return 1 + nodeOnenume(T->LeftTreeNode) + nodeOnenume(T->RightTreeNode);
    else
        return nodeOnenume(T->LeftTreeNode) + nodeOnenume(T->RightTreeNode);
    return 0;
}

//度为2的节点个数
int nodeTwonume(BiThrTree T){
    if(!T)
        return 0;
    else if(T->LeftTreeNode && T->RightTreeNode)
        return 1+nodeTwonume(T->LeftTreeNode) + nodeTwonume(T->RightTreeNode);
    else
        return nodeTwonume(T->LeftTreeNode) + nodeTwonume(T->RightTreeNode);
    return 0;
}
//交换左右子树
void exchangeTree(BiThrTree *T){
    if(*T){
        BiThrTree temp = (*T)->LeftTreeNode;
        (*T)->LeftTreeNode = (*T)->RightTreeNode;
        (*T)->RightTreeNode = temp;
        
        exchangeTree(&(*T)->LeftTreeNode);
        exchangeTree(&(*T)->RightTreeNode);
    }
}

int main(int argc, const char * argv[]) {
    // insert code here...
    printf("Hello, World!\n");
    //abc  d  ef  g  
    BiThrTree Tree = NULL;
    CreatBinarTreeNode(&Tree);
    putout(Tree);
    
    printf("\n");
    printf("叶子点的个数%d",Leafnum(Tree));
    
    printf("\n");
    printf("节点的个数%d",nodeNum(Tree));
    
    printf("\n");
    printf("高度%d",heightBitree(Tree));
    
    printf("\n");
    printf("度为1的个数:%d",nodeOnenume(Tree));
    
    printf("\n");
    printf("度为2的个数:%d",nodeTwonume(Tree));
    
    exchangeTree(&Tree);
    putout(Tree);
    return 0;
}