二叉树前中后序遍历

#include<cstdio>
#include<cstdlib>
typedef struct node{
	int data;
	struct node* left;
	struct node* right;
}Node;
void preorder(Node* root){
	if(root == NULL) return;
	printf("%d ",root->data); //注意这里是指针所以要用箭头 
	preorder(root->left);
	preorder(root->right);
}
void inorder(Node* root){
	if(root == NULL) return;
	inorder(root->left);
	printf("%d ",root->data);
	inorder(root->right);
} 

void postorder(Node* root){
	if(root == NULL) return ;
	postorder(root->left);
	postorder(root->right);
	printf("%d ",root->data);
}
int main(){
	Node n1;
	Node n2;
	Node n3;
	Node n4;
	
	n1.data = 5;
	n2.data = 6;
	n3.data = 7;
	n4.data = 8;
	
	n1.left  = &n2;
	n1.right = &n3;
	n2.left  = &n4;
	n2.right = NULL;
	n3.left  = NULL;
	n3.right = NULL;
	n4.left  = NULL;
	n4.right = NULL;
	
	preorder(&n1);
	putchar(10);
	inorder(&n1);
	putchar(10);
	postorder(&n1);
	return 0;
}

二叉搜索树的高度和最值

#include<cstdio>
#include<cstdlib>
typedef struct node{
	int data;
	struct node* left;
	struct node* right;
}Node;

typedef struct{
	Node* root;
}Tree;

void preorder(Node* root){
	if(root == NULL) return;
	printf("%d ",root->data); //注意这里是指针所以要用箭头 
	preorder(root->left);
	preorder(root->right);
}
void inorder(Node* root){
	if(root == NULL) return;
	inorder(root->left);
	printf("%d ",root->data);
	inorder(root->right);
} 

void postorder(Node* root){
	if(root == NULL) return ;
	postorder(root->left);
	postorder(root->right);
	printf("%d ",root->data);
}
int max(int a, int b){
	return a>b?a:b;
}
int get_height(Node* node){
	if(node == NULL) return 0;
	return max(get_height(node->left), get_height(node->right)) + 1;
}
int get_maximum(Node* node){
	if(node == NULL){
		return -1;  //返回-1表示为空树 
	}
	int maxl = get_maximum(node->left);
	int maxr = get_maximum(node->right);
	int maxc = node->data;
	if(maxl > maxc) maxc = maxl;
	if(maxr > maxc) maxc = maxr;
	return maxc; 
}
void insert(Tree* tree, int value){
	Node* node = (Node*)malloc(sizeof(Node));
	node->data = value;
	node->left = NULL;
	node->right= NULL;
	
	if(tree->root == NULL){
		tree->root = node;
	}else{
		Node* temp = tree->root;
		while(temp!=NULL){
			if(temp->data > value){
				if(temp->left == NULL){
					temp->left = node;
					return;
				}else{
					temp = temp->left;
				}
			}else{
				if(temp->right == NULL){
					temp->right = node;
					return;
				}
				else{
					temp = temp->right;
				}
			}
		}
	}
}
int main(){
	int arr[]={6,3,8,2,5,1,7};
	Tree tree;
	tree.root = NULL;
	for(int i=0;i<7;i++){
		insert(&tree, arr[i]);
	}
	preorder(tree.root); //前序遍历 
	putchar(10); 		//换行 
	inorder(tree.root);   
	putchar(10);
	postorder(tree.root);
	putchar(10);

	int h = get_height(tree.root);
	printf("h = %d\n",h);
	
	int mx = get_maximum(tree.root);
	printf("max = %d\n",mx);
	return 0;
}