Linked list realizes binary tree
#include<stdio.h>
#include<windows.h>
#include<stdbool.h>
//二叉树的实现和基本操作
typedef char Data;
typedef struct btree{
Data _data;
struct btree* _left;
struct btree* _right;
}btree;
//必须是指定的#->代表空
//创建二叉树
//将arr数组的字符写在二叉树 idx为arr的索引 =0
//这个函数是错的,因为在返回root的时候,内嵌函数的idx++后的结果也释放掉了
//上一个函数的idx依旧是没++之前的idx,所以所得到的二叉树不正确
//idx必须为全局变量,不能被函数的结束而消散,或者利用指针来操作
btree* createbtree1(Data*arr, int idx){
//错误
if (arr[idx] == '#'){
idx++;
return NULL;
}
else{
//创建根
btree* root = (btree*)malloc(sizeof(btree));
root->_data = arr[idx];
idx++;
root->_left = createbtree1(arr, idx);
root->_right = createbtree1(arr, idx);
return root;
}
}
btree* createbtree2(Data* arr, int *idx){
if (arr[*idx] == '#'){
//解引用
(*idx)++;
return NULL;
}
else{
//创建根
btree* root = (btree*)malloc(sizeof(btree));
root->_data = arr[*idx];
(*idx)++;
root->_left = createbtree1(arr, idx);
root->_right = createbtree1(arr, idx);
return root;
}
}
//前中后序遍历打印
void preorder(btree* tree){
if (tree){
printf("%d", tree->_data);
preorder(tree->_left);
preorder(tree->_right);
}
}
void inorder(btree* tree){
if (tree){
preorder(tree->_left);
printf("%d", tree->_data);
preorder(tree->_right);
}
}
void postorder(btree* tree){
if (tree){
preorder(tree->_left);
preorder(tree->_right);
printf("%d", tree->_data);
}
}
//返回结点数
int size1(btree* tree){
if (tree == NULL){
return 0;
}
return size(tree->_left) + size(tree->_right) + 1;
//1是自身
}
//叶子结点
int leafsize(btree* tree){
if (tree == NULL){
return 0;
}
if (tree->_left == NULL&&tree->_right == NULL){
return 1;
}
return
leafsize(tree->_left)+
leafsize(tree->_right);
}
//第k层的节点数
int ksize(btree* tree,int k){
if (tree == NULL){
return 0;
}
if (k == 1){
return 1;
}
return ksize(tree->_left, k - 1) + ksize(tree->_right, k - 1);
}
//找节点
btree* findtree(btree* tree, Data data){
if (tree->_data == data){
return tree;
}
if (tree == NULL){
return NULL;
}
btree* node=findtree(tree->_left, data);
if (node){
//因为返回值要么是呢个节点要么空
return node;
}
return findtree(tree->_right, data);
}
//二叉树销毁
//不是二级指针的话,销毁得是拷贝,并不是原数据
void xdistory(btree* a){
//错误
distory(a->_left);
distory(a->_right);
free(a);
a = NULL;
}
void distory(btree** a){
if (a == NULL){
//非法
return;
}
if (*a == NULL){
//空树
return;
}
distory(&((*a)->_left));
distory(&((*a)->_right));
free(*a);
*a = NULL;//根节点将根节点指向空，防止成为野指针
}