Complete code:
#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
typedef char datatype;
//二叉树的结点 二叉链
typedef struct BinaryTreeNode
{
struct Node* left;
struct Node* right;
datatype data;
}Node;
typedef struct BTree
{
//二叉树根节点
Node* root;
}BTree;
//创建二叉树，返回根节点
Node* Creattree(datatype arr[], int* idx)
{
if (arr[*idx] == '#')
{
(*idx)++;
return NULL;
}
//当前树的根节点
Node* root = (Node*)malloc(sizeof(Node));
root->data = arr[*idx];
(*idx)++;
//创建左右子树
root->left = Creattree(arr, idx);
root->right = Creattree(arr, idx);
return root;
}
//前序遍历
void preorder(Node* root)
{
if (root)
{
//前序：根->左->右
printf("%c ", root->data);
preorder(root->left);
preorder(root->right);
}
}
//中序遍历
void inorder(Node* root)
{
if (root)
{
//中序：左->根->右
inorder(root->left);
printf("%c ", root->data);
inorder(root->right);
}
}
//后序遍历
void postorder(Node* root)
{
if (root)
{
//后序：左->右->根
postorder(root->left);
postorder(root->right);
printf("%c ", root->data);
}
}
//二叉树结点个数
int BTreeSize(Node* root)
{
if (root == NULL)
return 0;
return BTreeSize(root->left) + BTreeSize(root->right) + 1;
}
//树的高度
int BTreeHigh(Node* root)
{
if (root == NULL)
return 0;
//树的高度=（左右子树中较大的度）+1
int left = BTreeHigh(root->left);
int right = BTreeHigh(root->right);
return left > right ? left + 1 : right + 1;
}
//二叉树叶子节点的个数
int BTreeLeaf(Node* root)
{
//空树
if (root == NULL)
return 0;
//该树只有一个结点
if (root->left == NULL && root->right == NULL)
return 1;
//一般情况
return BTreeLeaf(root->left) + BTreeLeaf(root->right);
}
//第K层结点个数=左右子树第k-1层节点个数的和 根为第一层
int BTreeKsize(Node* root,int k)
{
if (root == NULL)
return 0;
if (k == 1)
return 1;
return BTreeKsize(root->left,k-1)+BTreeKsize(root->right,k-1);
}
//二叉树查找
Node* BTreeFind(Node* root, datatype ch)
{
if (root)
{
if (root->data == ch)
return root;
Node* node = BTreeFind(root->left, ch);
if (node)
return node;
else
return BTreeFind(root->right, ch);
}
else
return NULL;
}
//销毁二叉树
void DestoryBTree(Node* root)
{
if (root)
{
DestoryBTree(root->left);
DestoryBTree(root->right);
free(root);
root = NULL;
}
}
void test()
{
char arr[] = "ABD##E#H##CF##G##";
int idx = 0;
Node* root = Creattree(arr, &idx);
preorder(root);
printf("\n");
inorder(root);
printf("\n");
postorder(root);
printf("\n");
printf("树的结点个数：%d \n", BTreeSize(root));
printf("树的度：%d \n", BTreeHigh(root));
printf("叶子节点的个数：%d \n", BTreeLeaf(root));
printf("第%d层的节点个数：%d \n",4, BTreeKsize(root,4));
}
int main()
{
test();
return 0;
}
operation result:
