查找二叉树的插入和遍历

2020年3月21日 98次阅读 
typedef struct BSTree{
	int data;
	BSTree *pLeft;
	BSTree *pRight;
}Node;

Node * BuyNewNode(int num)
{
	Node * pNode = new(Node);
	//assert(pNode);
	pNode->data = num;
	pNode->pLeft = NULL;
	pNode->pRight = NULL;
	return pNode;
}

Node * insert(int num, Node * root) {
	if (root == NULL) {
		root = BuyNewNode(num);
	} else {
	    if (num > root->data)
			root->pRight = insert(num,root->pRight);
		else if (num < root->data)
			root->pLeft= insert(num,root->pLeft);
	}
	return root;
}

int main()
{
	int input[10] = {10,6,14,4,8,12,16,5,7,13};

	Node *root = NULL;
	Node *Head = NULL;
	for(int i = 0; i<10; i++) {
		root = insert(input[i],root);
		if (i==0)
			Head = root;
	}
	return 0;
}

中序遍历递归程序如下：

void link(Node *root) {

	if(root == NULL)
		return;

	if(root->pLeft) {              // 1.
	   link(root->pLeft);
	}

	printf("%d ", root->data);     // 2.
	
	if(root->pRight) {             // 3.
	    link(root->pRight);
	}
}

只要把中序的语句调一下顺序就是前序遍历和后序遍历

前序：2->1->3

后序：1->3->2

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