目录

树结构及其算法-二叉查找树

C++代码

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树结构及其算法-二叉查找树

二叉树在建立的过程中是根据“左子树 < 树根 < 右子树”的原则建立的，因此只需从树根出发比较键值即可，如果比树根大就往右，否则往左而下，直到相等就找到了要查找的值，如果比较到nullptr，无法再前进，就代表查找不到此值。

    TreeNode* Find(TreeNode* tree, int value) {
		while (true) {
			if (tree == nullptr)
				return nullptr;
			if (tree->data == value)
				return tree;
			else if (tree->data > value)
				tree = tree->leftNode;
			else
				tree = tree->rightNode;
		}
	}

C++代码

#include<iostream>
using namespace std;

struct TreeNode {
	int data;
	TreeNode* leftNode;
	TreeNode* rightNode;
	TreeNode(int tempData, TreeNode* tempLeftNode = nullptr, TreeNode* tempRightNode = nullptr) {
		this->data = tempData;
		this->leftNode = tempLeftNode;
		this->rightNode = tempRightNode;
	}
};

class Tree {
private:
	TreeNode* treeNode;
public:
	Tree() {
		treeNode = nullptr;
	}
	TreeNode* GetTreeNode() {
		return this->treeNode;
	}
	void AddNodeToTree(int* tempData, int tempSize) {
		for (int i = 0; i < tempSize; i++) {
			TreeNode* currentNode;
			TreeNode* newNode;
			int flag = 0;
			newNode = new TreeNode(tempData[i]);
			if (treeNode == nullptr)
				treeNode = newNode;
			else {
				currentNode = treeNode;
				while (!flag) {
					if (tempData[i] < currentNode->data) {
						if (currentNode->leftNode == nullptr) {
							currentNode->leftNode = newNode;
							flag = 1;
						}
						else
							currentNode = currentNode->leftNode;
					}
					else {
						if (currentNode->rightNode == nullptr) {
							currentNode->rightNode = newNode;
							flag = 1;
						}
						else
							currentNode = currentNode->rightNode;
					}
				}
			}
		}
	}
	void Inorder(TreeNode* tempTree) {
		if (tempTree != nullptr) {
			Inorder(tempTree->leftNode);
			cout << tempTree->data << " ";
			Inorder(tempTree->rightNode);
		}
	}
	TreeNode* Find(TreeNode* tree, int value) {
		while (true) {
			if (tree == nullptr)
				return nullptr;
			if (tree->data == value)
				return tree;
			else if (tree->data > value)
				tree = tree->leftNode;
			else
				tree = tree->rightNode;
		}
	}
};

int main() {
	int data[]{ 7,4,1,5,16,8,11,12,15,9,2 };
	cout << "原始数据：" << endl;
	for (int i = 0; i < 11; i++)
		cout << data[i] << " ";
	cout << endl;

	Tree* tree = new Tree;
	tree->AddNodeToTree(data, 11);
	cout << "中序遍历：" << endl;
	tree->Inorder(tree->GetTreeNode());
	cout << endl;

	cout << "请输入要查找的值：";
	int value;
	cin >> value;
	if ((tree->Find(tree->GetTreeNode(), value)) != nullptr)
		cout << "您要找的值[" << tree->Find(tree->GetTreeNode(), value)->data << "]找到了" << endl;
	else
		cout << "您要找的值没有找到" << endl;

	return 0;
}

输出结果