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BSTree
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167 lines (158 loc) · 2.66 KB
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#pragma once
#include<iostream>
template<class k>
struct BSTNode
{
k value;
struct BSTNode<k>* left;
struct BSTNode<k>* right;
BSTNode(const k& val)
:value(val), left(nullptr), right(nullptr)
{}
};
template<class k>
class BSTree
{
typedef BSTNode<k> Node;
public:
bool Insert(const k& val)
{
//根节点为空格，直接插入
if (root == nullptr)
{
root = new Node(val);
return true;
}
//根节点不为空，先找到合适的位置，在插入
Node* parent = root;
Node* cur = root;
while (cur)
{
//如果找到相同节点，则不需要插入
if (cur->value == val)
{
return false;
}
else if (cur->value < val)
{
parent = cur;
cur = cur->right;
}
else
{
parent = cur;
cur = cur->left;
}
}
//找到了，创建节点进行插入
Node* tmp = new Node(val);
if (parent->value < val)
{
parent->right = tmp;
}
else
{
parent->left = tmp;
}
return true;
}
const Node* find(const k& val)
{
Node* cur = root;
while (cur)
{
if (cur->value == val)
{
return cur;
}
else if (cur->value < val)
{
cur = cur->right;
}
else
{
cur = cur->left;
}
}
return nullptr;
}
bool Erase(const k& val)
{
//查找
Node* parent = nullptr;
Node* cur = root;
while (cur)
{
if (cur->value > val)
{
//在左子树
parent = cur;
cur = cur->left;
}
else if (cur->value < val)
{
//在右子树找
parent = cur;
cur = cur->right;
}
else
{
//找到了，删除
//左子树为空
if (cur->left == nullptr)
{
if (cur == root)
root = cur->right;
//父节点指向右子树
else
{
if (cur == parent->left)
{
parent->left = cur->right;
}
else
{
parent->right = cur->right;
}
}
}
else if (cur->right == nullptr)
{
if (cur == root)
root = cur->left;
else
{
if (cur == parent->left)
parent->left = cur->left;
else
parent->right = cur->left;
}
}
else
{
//左右子树都不为空，找右树的最小节点
Node* minNode = cur->right;
Node* minNodeParent = cur;
while (minNode->left)
{
minNodeParent = minNode;
minNode = minNode->left;
}
//将要删除的节点和该节点交换
cur->value = minNode->value;
//删除交换后的节点
if (minNodeParent->left == minNode)
minNodeParent->left = minNode->right;
else
minNodeParent->right = minNode->right;
//删除节点
delete minNode;
}
return true;
}
}
return false;
}
public:
Node* root = nullptr;
};