CS_learn/hello-algo
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Format C++ codes in Clang-Format Style: Microsoft

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krahets
2023-04-14 03:44:02 +08:00
parent f8513455b5
commit 9c9c8b7574
46 changed files with 732 additions and 888 deletions
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103
codes/cpp/chapter_tree/binary_search_tree.cpp
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@@ -8,13 +8,13 @@
/* 二叉搜索树 */
class BinarySearchTree {
private:
TreeNode* root;
private:
TreeNode *root;
public:
public:
BinarySearchTree(vector<int> nums) {
sort(nums.begin(), nums.end()); // 排序数组
root = buildTree(nums, 0, nums.size() - 1); // 构建二叉搜索树
sort(nums.begin(), nums.end()); // 排序数组
root = buildTree(nums, 0, nums.size() - 1); // 构建二叉搜索树
}
~BinarySearchTree() {
@@ -22,16 +22,17 @@ public:
}
/* 获取二叉树根节点 */
TreeNode* getRoot() {
TreeNode *getRoot() {
return root;
}
/* 构建二叉搜索树 */
TreeNode* buildTree(vector<int> nums, int i, int j) {
if (i > j) return nullptr;
TreeNode *buildTree(vector<int> nums, int i, int j) {
if (i > j)
return nullptr;
// 将数组中间节点作为根节点
int mid = (i + j) / 2;
TreeNode* root = new TreeNode(nums[mid]);
TreeNode *root = new TreeNode(nums[mid]);
// 递归建立左子树和右子树
root->left = buildTree(nums, i, mid - 1);
root->right = buildTree(nums, mid + 1, j);
@@ -39,74 +40,90 @@ public:
}
/* 查找节点 */
TreeNode* search(int num) {
TreeNode* cur = root;
TreeNode *search(int num) {
TreeNode *cur = root;
// 循环查找，越过叶节点后跳出
while (cur != nullptr) {
// 目标节点在 cur 的右子树中
if (cur->val < num) cur = cur->right;
if (cur->val < num)
cur = cur->right;
// 目标节点在 cur 的左子树中
else if (cur->val > num) cur = cur->left;
else if (cur->val > num)
cur = cur->left;
// 找到目标节点，跳出循环
else break;
else
break;
}
// 返回目标节点
return cur;
}
/* 插入节点 */
TreeNode* insert(int num) {
TreeNode *insert(int num) {
// 若树为空，直接提前返回
if (root == nullptr) return nullptr;
if (root == nullptr)
return nullptr;
TreeNode *cur = root, *pre = nullptr;
// 循环查找，越过叶节点后跳出
while (cur != nullptr) {
// 找到重复节点，直接返回
if (cur->val == num) return nullptr;
if (cur->val == num)
return nullptr;
pre = cur;
// 插入位置在 cur 的右子树中
if (cur->val < num) cur = cur->right;
if (cur->val < num)
cur = cur->right;
// 插入位置在 cur 的左子树中
else cur = cur->left;
else
cur = cur->left;
}
// 插入节点 val
TreeNode* node = new TreeNode(num);
if (pre->val < num) pre->right = node;
else pre->left = node;
TreeNode *node = new TreeNode(num);
if (pre->val < num)
pre->right = node;
else
pre->left = node;
return node;
}
/* 删除节点 */
TreeNode* remove(int num) {
TreeNode *remove(int num) {
// 若树为空，直接提前返回
if (root == nullptr) return nullptr;
if (root == nullptr)
return nullptr;
TreeNode *cur = root, *pre = nullptr;
// 循环查找，越过叶节点后跳出
while (cur != nullptr) {
// 找到待删除节点，跳出循环
if (cur->val == num) break;
if (cur->val == num)
break;
pre = cur;
// 待删除节点在 cur 的右子树中
if (cur->val < num) cur = cur->right;
if (cur->val < num)
cur = cur->right;
// 待删除节点在 cur 的左子树中
else cur = cur->left;
else
cur = cur->left;
}
// 若无待删除节点，则直接返回
if (cur == nullptr) return nullptr;
if (cur == nullptr)
return nullptr;
// 子节点数量 = 0 or 1
if (cur->left == nullptr || cur->right == nullptr) {
// 当子节点数量 = 0 / 1 时， child = nullptr / 该子节点
TreeNode* child = cur->left != nullptr ? cur->left : cur->right;
TreeNode *child = cur->left != nullptr ? cur->left : cur->right;
// 删除节点 cur
if (pre->left == cur) pre->left = child;
else pre->right = child;
if (pre->left == cur)
pre->left = child;
else
pre->right = child;
// 释放内存
delete cur;
}
// 子节点数量 = 2
else {
// 获取中序遍历中 cur 的下一个节点
TreeNode* nex = getInOrderNext(cur->right);
TreeNode *nex = getInOrderNext(cur->right);
int tmp = nex->val;
// 递归删除节点 nex
remove(nex->val);
@@ -117,8 +134,9 @@ public:
}
/* 获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况） */
TreeNode* getInOrderNext(TreeNode* root) {
if (root == nullptr) return root;
TreeNode *getInOrderNext(TreeNode *root) {
if (root == nullptr)
return root;
// 循环访问左子节点，直到叶节点时为最小节点，跳出
while (root->left != nullptr) {
root = root->left;
@@ -127,34 +145,33 @@ public:
}
};
/* Driver Code */
int main() {
/* 初始化二叉搜索树 */
vector<int> nums = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
BinarySearchTree* bst = new BinarySearchTree(nums);
vector<int> nums = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
BinarySearchTree *bst = new BinarySearchTree(nums);
cout << endl << "初始化的二叉树为\n" << endl;
PrintUtil::printTree(bst->getRoot());
printTree(bst->getRoot());
/* 查找节点 */
TreeNode* node = bst->search(7);
TreeNode *node = bst->search(7);
cout << endl << "查找到的节点对象为 " << node << "，节点值 = " << node->val << endl;
/* 插入节点 */
node = bst->insert(16);
cout << endl << "插入节点 16 后，二叉树为\n" << endl;
PrintUtil::printTree(bst->getRoot());
printTree(bst->getRoot());
/* 删除节点 */
bst->remove(1);
cout << endl << "删除节点 1 后，二叉树为\n" << endl;
PrintUtil::printTree(bst->getRoot());
printTree(bst->getRoot());
bst->remove(2);
cout << endl << "删除节点 2 后，二叉树为\n" << endl;
PrintUtil::printTree(bst->getRoot());
printTree(bst->getRoot());
bst->remove(4);
cout << endl << "删除节点 4 后，二叉树为\n" << endl;
PrintUtil::printTree(bst->getRoot());
printTree(bst->getRoot());
// 释放内存
delete bst;