题解 | 二叉排序树

#include <iostream>
#include <cstdlib>
using namespace std;
typedef struct TreeNode {
	int data;
	struct TreeNode *left,*right;
};
void preOrder(TreeNode *root) {
	if(root != NULL) {
		cout<<root->data<<" ";
		preOrder(root->left);
		preOrder(root->right);
	}
}
void inOrder(TreeNode *root) {
	if(root != NULL) {
		inOrder(root->left);
		cout<<root->data<<" ";
		inOrder(root->right);
	}
}
void postOrder(TreeNode *root) {
	if(root != NULL) {
		postOrder(root->left);
		postOrder(root->right);
		cout<<root->data<<" ";
	}
}
void insertBST(TreeNode* &root,int data) {
	if(root == NULL) {
		root = (TreeNode *)malloc(sizeof(TreeNode));
		root->data = data;
		root->left = NULL;
		root->right = NULL;
		return;
	} else	if(root->data > data) {
		insertBST(root->left,data);
	} else	if(root->data < data) {
		insertBST(root->right,data);
	}
}
int main() {
	int n = 0;
	while(cin>>n) {
		TreeNode* p = NULL;
		for(int i = 0 ; i < n; i++) {
			int input = 0;
			cin>>input;
			insertBST(p,input);
		}
		preOrder(p);
		cout<<endl;
		inOrder(p);
		cout<<endl;
		postOrder(p);
		cout<<endl;
	}
	return 0;
}

1、可能有多组测试数据的时候 输入一定要写为 while(cin>>n)！