DSOJ BST（二叉搜索树）

题目链接

#include<stdio.h>			//Binary Search Tree
#include<stdlib.h>

typedef struct node
{
	int data;
	struct node *left, *right;
}BST;

BST *insert(BST *T, int key)		//Insert
{
	if (!T)
	{
		T = (BST *)malloc(sizeof(BST));
		T->data = key;
		T->left = T->right = NULL;
		return T;
	}
	if (T->data == key) return T;
	if (T->data > key) T->left = insert(T->left, key);
	else T->right = insert(T->right, key);
	return T;
}

BST *create()			//Create
{
	BST *T;
	int key;
	char c;
	T = NULL;
	do
	{
		scanf("%d", &key);
		T = insert(T, key);
		c = getchar();
	} while (c == ' ');
	return T;
}

void preorder(BST *T)		//Preorder Traversal
{
	if (!T) return;
	printf("%d ", T->data);
	preorder(T->left);
	preorder(T->right);
}

int main()
{
	BST *T;
	T = create();
	preorder(T);
	printf("\n");
	return 0;
}