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cpp-algo-cases/chapter_tree/binary_search_tree.cpp

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2024-02-20 16:13:23 +08:00
/**
* File: binary_search_tree.cpp
* Created Time: 2022-11-25
* Author: krahets (krahets@163.com)
*/
#include "../utils/common.hpp"
/* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
class BinarySearchTree {
private:
TreeNode *root;
public:
/* <20><><EFBFBD>췽<EFBFBD><ECB7BD> */
BinarySearchTree() {
// <20><>ʼ<EFBFBD><CABC><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
root = nullptr;
}
/* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
~BinarySearchTree() {
freeMemoryTree(root);
}
/* <20><>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD> */
TreeNode *getRoot() {
return root;
}
/* <20><><EFBFBD>ҽڵ<D2BD> */
TreeNode *search(int num) {
TreeNode *cur = root;
// ѭ<><D1AD><EFBFBD><EFBFBD><EFBFBD>ң<EFBFBD>Խ<EFBFBD><D4BD>Ҷ<EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
while (cur != nullptr) {
// Ŀ<><C4BF><EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD> cur <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
if (cur->val < num)
cur = cur->right;
// Ŀ<><C4BF><EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD> cur <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
else if (cur->val > num)
cur = cur->left;
// <20>ҵ<EFBFBD>Ŀ<EFBFBD><C4BF><EFBFBD>ڵ㣬<DAB5><E3A3AC><EFBFBD><EFBFBD>ѭ<EFBFBD><D1AD>
else
break;
}
// <20><><EFBFBD><EFBFBD>Ŀ<EFBFBD><C4BF><EFBFBD>ڵ<EFBFBD>
return cur;
}
/* <20><><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD> */
void insert(int num) {
// <20><><EFBFBD><EFBFBD>Ϊ<EFBFBD>գ<EFBFBD><D5A3><EFBFBD><EFBFBD><EFBFBD>ʼ<EFBFBD><CABC><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD>
if (root == nullptr) {
root = new TreeNode(num);
return;
}
TreeNode *cur = root, *pre = nullptr;
// ѭ<><D1AD><EFBFBD><EFBFBD><EFBFBD>ң<EFBFBD>Խ<EFBFBD><D4BD>Ҷ<EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
while (cur != nullptr) {
// <20>ҵ<EFBFBD><D2B5>ظ<EFBFBD><D8B8>ڵ㣬ֱ<E3A3AC>ӷ<EFBFBD><D3B7><EFBFBD>
if (cur->val == num)
return;
pre = cur;
// <20><><EFBFBD><EFBFBD>λ<EFBFBD><CEBB><EFBFBD><EFBFBD> cur <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
if (cur->val < num)
cur = cur->right;
// <20><><EFBFBD><EFBFBD>λ<EFBFBD><CEBB><EFBFBD><EFBFBD> cur <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
else
cur = cur->left;
}
// <20><><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD>
TreeNode *node = new TreeNode(num);
if (pre->val < num)
pre->right = node;
else
pre->left = node;
}
/* ɾ<><C9BE><EFBFBD>ڵ<EFBFBD> */
void remove(int num) {
// <20><><EFBFBD><EFBFBD>Ϊ<EFBFBD>գ<EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD><EFBFBD>ǰ<EFBFBD><C7B0><EFBFBD><EFBFBD>
if (root == nullptr)
return;
TreeNode *cur = root, *pre = nullptr;
// ѭ<><D1AD><EFBFBD><EFBFBD><EFBFBD>ң<EFBFBD>Խ<EFBFBD><D4BD>Ҷ<EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
while (cur != nullptr) {
// <20>ҵ<EFBFBD><D2B5><EFBFBD>ɾ<EFBFBD><C9BE><EFBFBD>ڵ㣬<DAB5><E3A3AC><EFBFBD><EFBFBD>ѭ<EFBFBD><D1AD>
if (cur->val == num)
break;
pre = cur;
// <20><>ɾ<EFBFBD><C9BE><EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD> cur <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
if (cur->val < num)
cur = cur->right;
// <20><>ɾ<EFBFBD><C9BE><EFBFBD>ڵ<EFBFBD><DAB5><EFBFBD> cur <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
else
cur = cur->left;
}
// <20><><EFBFBD>޴<EFBFBD>ɾ<EFBFBD><C9BE><EFBFBD>ڵ㣬<DAB5><E3A3AC>ֱ<EFBFBD>ӷ<EFBFBD><D3B7><EFBFBD>
if (cur == nullptr)
return;
// <20>ӽڵ<D3BD><DAB5><EFBFBD><EFBFBD><EFBFBD> = 0 or 1
if (cur->left == nullptr || cur->right == nullptr) {
// <20><><EFBFBD>ӽڵ<D3BD><DAB5><EFBFBD><EFBFBD><EFBFBD> = 0 / 1 ʱ<><CAB1> child = nullptr / <20><><EFBFBD>ӽڵ<D3BD>
TreeNode *child = cur->left != nullptr ? cur->left : cur->right;
// ɾ<><C9BE><EFBFBD>ڵ<EFBFBD> cur
if (cur != root) {
if (pre->left == cur)
pre->left = child;
else
pre->right = child;
} else {
// <20><>ɾ<EFBFBD><C9BE><EFBFBD>ڵ<EFBFBD>Ϊ<EFBFBD><CEAA><EFBFBD>ڵ㣬<DAB5><E3A3AC><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ָ<EFBFBD><D6B8><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD>
root = child;
}
// <20>ͷ<EFBFBD><CDB7>ڴ<EFBFBD>
delete cur;
}
// <20>ӽڵ<D3BD><DAB5><EFBFBD><EFBFBD><EFBFBD> = 2
else {
// <20><>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> cur <20><><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD>ڵ<EFBFBD>
TreeNode *tmp = cur->right;
while (tmp->left != nullptr) {
tmp = tmp->left;
}
int tmpVal = tmp->val;
// <20>ݹ<EFBFBD>ɾ<EFBFBD><C9BE><EFBFBD>ڵ<EFBFBD> tmp
remove(tmp->val);
// <20><> tmp <20><><EFBFBD><EFBFBD> cur
cur->val = tmpVal;
}
}
};
/* Driver Code */
int main() {
/* <20><>ʼ<EFBFBD><CABC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
BinarySearchTree *bst = new BinarySearchTree();
// <20><>ע<EFBFBD>⣬<EFBFBD><E2A3AC>ͬ<EFBFBD>IJ<EFBFBD><C4B2><EFBFBD>˳<EFBFBD><CBB3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɲ<EFBFBD>ͬ<EFBFBD>Ķ<EFBFBD><C4B6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>п<EFBFBD><D0BF><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
vector<int> nums = {8, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13, 15};
for (int num : nums) {
bst->insert(num);
}
cout << endl << "<EFBFBD><EFBFBD>ʼ<EFBFBD><EFBFBD><EFBFBD>Ķ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ\n" << endl;
printTree(bst->getRoot());
/* <20><><EFBFBD>ҽڵ<D2BD> */
TreeNode *node = bst->search(7);
cout << endl << "<EFBFBD><EFBFBD><EFBFBD>ҵ<EFBFBD><EFBFBD>Ľڵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ " << node << "<EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD>ֵ = " << node->val << endl;
/* <20><><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD> */
bst->insert(16);
cout << endl << "<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD> 16 <20>󣬶<EFBFBD><F3A3ACB6><EFBFBD><EFBFBD><EFBFBD>Ϊ\n" << endl;
printTree(bst->getRoot());
/* ɾ<><C9BE><EFBFBD>ڵ<EFBFBD> */
bst->remove(1);
cout << endl << "ɾ<EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD> 1 <20>󣬶<EFBFBD><F3A3ACB6><EFBFBD><EFBFBD><EFBFBD>Ϊ\n" << endl;
printTree(bst->getRoot());
bst->remove(2);
cout << endl << "ɾ<EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD> 2 <20>󣬶<EFBFBD><F3A3ACB6><EFBFBD><EFBFBD><EFBFBD>Ϊ\n" << endl;
printTree(bst->getRoot());
bst->remove(4);
cout << endl << "ɾ<EFBFBD><EFBFBD><EFBFBD>ڵ<EFBFBD> 4 <20>󣬶<EFBFBD><F3A3ACB6><EFBFBD><EFBFBD><EFBFBD>Ϊ\n" << endl;
printTree(bst->getRoot());
// <20>ͷ<EFBFBD><CDB7>ڴ<EFBFBD>
delete bst;
return 0;
}