二叉排序树的基本操作

二叉排序树定义

typedef struct BTNode {
	int val;
	struct BTNode *lchild;
	struct BTNode *rchild;
} BSTNode, *BiTree;

查找

BTNode *BST_Search(BiTree T, int key, BTNode *p) {
	p = NULL;
	while(key < T->val && key != T->val) {
		p = T;
		if(key < T->val)	T = T->lchild;
		else T = T->rchild;
	}
	return T;
}

插入

int BST_Insert(BiTree &T, int k) {
	if(T == NULL) {                 //原树为空，新插入的记录为根结点
		T = (BiTree)malloc(sizeof(BTNode));
		T->val = k;
		T->lchild = T->rchild = NULL;
		return 1;
	} else if(k == T->val)
		return 0;
	else if(k < T->val)
		return BST_Insert(T->lchild, k);
	else
		return BST_Insert(T->rchild, k);
}

构造

void Create_BST(BiTree &T, int *A, int n) {
	T = NULL;
	for(int i = 0; i < n; i++) {
		BST_Insert(T, A[i]);
	}
}