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https://github.com/krahets/hello-algo.git
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Merge branch 'master' into binary_search_tree
This commit is contained in:
Yudong Jin
@@ -1,228 +0,0 @@
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/*
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* File: avl_tree.cpp
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* Created Time: 2022-12-2
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* Author: mgisr (maguagua0706@gmail.com)
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*/
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#include "../include/include.hpp"
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class AvlTree {
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private:
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TreeNode *root{};
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static bool isBalance(const TreeNode *p);
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static int getBalanceFactor(const TreeNode *p);
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static void updateHeight(TreeNode *p);
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void fixBalance(TreeNode *p);
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static bool isLeftChild(const TreeNode *p);
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static TreeNode *&fromParentTo(TreeNode *node);
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public:
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AvlTree() = default;
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AvlTree(const AvlTree &p) = default;
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const TreeNode *search(int val);
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bool insert(int val);
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bool remove(int val);
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void printTree();
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};
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// 判断该结点是否平衡
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bool AvlTree::isBalance(const TreeNode *p) {
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int balance_factor = getBalanceFactor(p);
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if (-1 <= balance_factor && balance_factor <= 1) { return true; }
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else { return false; }
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}
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// 获取当前结点的平衡因子
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int AvlTree::getBalanceFactor(const TreeNode *p) {
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if (p->left == nullptr && p->right == nullptr) { return 0; }
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else if (p->left == nullptr) { return (-1 - p->right->height); }
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else if (p->right == nullptr) { return p->left->height + 1; }
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else { return p->left->height - p->right->height; }
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}
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// 更新结点高度
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void AvlTree::updateHeight(TreeNode *p) {
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if (p->left == nullptr && p->right == nullptr) { p->height = 0; }
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else if (p->left == nullptr) { p->height = p->right->height + 1; }
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else if (p->right == nullptr) { p->height = p->left->height + 1; }
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else { p->height = std::max(p->left->height, p->right->height) + 1; }
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}
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void AvlTree::fixBalance(TreeNode *p) {
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// 左旋操作
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auto rotate_left = [&](TreeNode *node) -> TreeNode * {
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TreeNode *temp = node->right;
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temp->parent = p->parent;
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node->right = temp->left;
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if (temp->left != nullptr) {
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temp->left->parent = node;
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}
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temp->left = node;
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node->parent = temp;
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updateHeight(node);
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updateHeight(temp);
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return temp;
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};
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// 右旋操作
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auto rotate_right = [&](TreeNode *node) -> TreeNode * {
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TreeNode *temp = node->left;
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temp->parent = p->parent;
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node->left = temp->right;
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if (temp->right != nullptr) {
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temp->right->parent = node;
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}
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temp->right = node;
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node->parent = temp;
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updateHeight(node);
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updateHeight(temp);
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return temp;
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};
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// 根据规则选取旋转方式
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if (getBalanceFactor(p) > 1) {
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if (getBalanceFactor(p->left) > 0) {
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if (p->parent == nullptr) { root = rotate_right(p); }
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else { fromParentTo(p) = rotate_right(p); }
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} else {
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p->left = rotate_left(p->left);
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if (p->parent == nullptr) { root = rotate_right(p); }
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else { fromParentTo(p) = rotate_right(p); }
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}
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} else {
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if (getBalanceFactor(p->right) < 0) {
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if (p->parent == nullptr) { root = rotate_left(p); }
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else { fromParentTo(p) = rotate_left(p); }
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} else {
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p->right = rotate_right(p->right);
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if (p->parent == nullptr) { root = rotate_left(p); }
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else { fromParentTo(p) = rotate_left(p); }
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}
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}
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}
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// 判断当前结点是否为其父节点的左孩子
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bool AvlTree::isLeftChild(const TreeNode *p) {
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if (p->parent == nullptr) { return false; }
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return (p->parent->left == p);
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}
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// 返回父节点指向当前结点指针的引用
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TreeNode *&AvlTree::fromParentTo(TreeNode *node) {
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if (isLeftChild(node)) { return node->parent->left; }
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else { return node->parent->right; }
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}
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const TreeNode *AvlTree::search(int val) {
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TreeNode *p = root;
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while (p != nullptr) {
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if (p->val == val) { return p; }
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else if (p->val > val) { p = p->left; }
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else { p = p->right; }
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}
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return nullptr;
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}
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bool AvlTree::insert(int val) {
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TreeNode *p = root;
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if (p == nullptr) {
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root = new TreeNode(val);
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return true;
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}
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for (;;) {
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if (p->val == val) { return false; }
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else if (p->val > val) {
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if (p->left == nullptr) {
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p->left = new TreeNode(val, p);
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break;
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} else {
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p = p->left;
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}
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} else {
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if (p->right == nullptr) {
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p->right = new TreeNode(val, p);
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break;
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} else {
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p = p->right;
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}
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}
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}
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for (; p != nullptr; p = p->parent) {
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if (!isBalance(p)) {
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fixBalance(p);
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break;
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} else { updateHeight(p); }
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}
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return true;
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}
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bool AvlTree::remove(int val) {
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TreeNode *p = root;
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if (p == nullptr) { return false; }
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while (p != nullptr) {
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if (p->val == val) {
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TreeNode *real_delete_node = p;
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TreeNode *next_node;
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if (p->left == nullptr) {
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next_node = p->right;
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if (p->parent == nullptr) { root = next_node; }
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else { fromParentTo(p) = next_node; }
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} else if (p->right == nullptr) {
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next_node = p->left;
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if (p->parent == nullptr) { root = next_node; }
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else { fromParentTo(p) = next_node; }
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} else {
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while (real_delete_node->left != nullptr) {
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real_delete_node = real_delete_node->left;
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}
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std::swap(p->val, real_delete_node->val);
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next_node = real_delete_node->right;
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if (real_delete_node->parent == p) { p->right = next_node; }
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else { real_delete_node->parent->left = next_node; }
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}
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if (next_node != nullptr) {
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next_node->parent = real_delete_node->parent;
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}
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for (p = real_delete_node; p != nullptr; p = p->parent) {
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if (!isBalance(p)) { fixBalance(p); }
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updateHeight(p);
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}
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delete real_delete_node;
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return true;
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} else if (p->val > val) {
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p = p->left;
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} else {
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p = p->right;
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}
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}
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return false;
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}
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void inOrder(const TreeNode *root) {
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if (root == nullptr) return;
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inOrder(root->left);
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cout << root->val << ' ';
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inOrder(root->right);
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}
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void AvlTree::printTree() {
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inOrder(root);
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cout << endl;
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}
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int main() {
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AvlTree tree = AvlTree();
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// tree.insert(13);
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// tree.insert(24);
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// tree.insert(37);
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// tree.insert(90);
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// tree.insert(53);
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tree.insert(53);
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tree.insert(90);
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tree.insert(37);
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tree.insert(24);
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tree.insert(13);
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tree.remove(90);
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tree.printTree();
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const TreeNode *p = tree.search(37);
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cout << p->val;
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return 0;
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}
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@@ -1,4 +1,4 @@
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/*
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/**
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* File: binary_search_tree.cpp
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* Created Time: 2022-11-25
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* Author: Krahets (krahets@163.com)
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@@ -96,11 +96,13 @@ public:
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// 删除结点 cur
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if (pre->left == cur) pre->left = child;
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else pre->right = child;
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// 释放内存
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delete cur;
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}
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// 子结点数量 = 2
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else {
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// 获取中序遍历中 cur 的下一个结点
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TreeNode* nex = min(cur->right);
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TreeNode* nex = getInOrderNext(cur->right);
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int tmp = nex->val;
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// 递归删除结点 nex
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remove(nex->val);
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@@ -110,8 +112,8 @@ public:
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return cur;
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}
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/* 获取最小结点 */
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TreeNode* min(TreeNode* root) {
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/* 获取中序遍历中的下一个结点（仅适用于 root 有左子结点的情况） */
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TreeNode* getInOrderNext(TreeNode* root) {
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if (root == nullptr) return root;
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// 循环访问左子结点，直到叶结点时为最小结点，跳出
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while (root->left != nullptr) {
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@@ -1,4 +1,4 @@
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/*
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/**
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* File: binary_tree.cpp
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* Created Time: 2022-11-25
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* Author: Krahets (krahets@163.com)
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@@ -33,6 +33,7 @@ int main() {
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PrintUtil::printTree(n1);
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// 删除结点 P
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n1->left = n2;
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delete P; // 释放内存
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cout << endl << "删除结点 P 后\n" << endl;
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PrintUtil::printTree(n1);
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@@ -1,4 +1,4 @@
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/*
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/**
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* File: binary_tree_bfs.cpp
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* Created Time: 2022-11-25
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* Author: Krahets (krahets@163.com)
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@@ -30,8 +30,7 @@ vector<int> hierOrder(TreeNode* root) {
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int main() {
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/* 初始化二叉树 */
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// 这里借助了一个从数组直接生成二叉树的函数
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TreeNode* root = vecToTree(vector<int>
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{ 1, 2, 3, 4, 5, 6, 7, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX });
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TreeNode* root = vecToTree(vector<int> { 1, 2, 3, 4, 5, 6, 7 });
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cout << endl << "初始化二叉树\n" << endl;
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PrintUtil::printTree(root);
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@@ -1,4 +1,4 @@
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/*
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/**
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* File: binary_tree_dfs.cpp
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* Created Time: 2022-11-25
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* Author: Krahets (krahets@163.com)
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@@ -41,8 +41,7 @@ void postOrder(TreeNode* root) {
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int main() {
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/* 初始化二叉树 */
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// 这里借助了一个从数组直接生成二叉树的函数
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TreeNode* root = vecToTree(vector<int>
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{ 1, 2, 3, 4, 5, 6, 7, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX, INT_MAX});
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TreeNode* root = vecToTree(vector<int> { 1, 2, 3, 4, 5, 6, 7 });
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cout << endl << "初始化二叉树\n" << endl;
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PrintUtil::printTree(root);
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