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krahets
2023-04-14 04:01:38 +08:00
parent cf431646e9
commit 4d318e8e6b
26 changed files with 469 additions and 295 deletions
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118
chapter_tree/binary_search_tree.md
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@@ -46,11 +46,14 @@ comments: true
// 循环查找，越过叶节点后跳出
while (cur != null) {
// 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;
@@ -61,16 +64,19 @@ comments: true
```cpp title="binary_search_tree.cpp"
/* 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;
@@ -259,22 +265,28 @@ comments: true
/* 插入节点 */
TreeNode insert(int num) {
// 若树为空，直接提前返回
if (root == null) return null;
if (root == null)
return null;
TreeNode cur = root, pre = null;
// 循环查找，越过叶节点后跳出
while (cur != null) {
// 找到重复节点，直接返回
if (cur.val == num) return null;
if (cur.val == num)
return null;
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;
if (pre.val < num)
pre.right = node;
else
pre.left = node;
return node;
}
```
@@ -283,24 +295,30 @@ comments: true
```cpp title="binary_search_tree.cpp"
/* 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;
}
```
@@ -588,27 +606,34 @@ comments: true
/* 删除节点 */
TreeNode remove(int num) {
// 若树为空，直接提前返回
if (root == null) return null;
if (root == null)
return null;
TreeNode cur = root, pre = null;
// 循环查找，越过叶节点后跳出
while (cur != null) {
// 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 == null) return null;
if (cur == null)
return null;
// 子节点数量 = 0 or 1
if (cur.left == null || cur.right == null) {
// 当子节点数量 = 0 / 1 时， child = null / 该子节点
TreeNode child = cur.left != null ? 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;
}
// 子节点数量 = 2
else {
@@ -625,7 +650,8 @@ comments: true
/* 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 == null) return root;
if (root == null)
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 != null) {
root = root.left;
@@ -638,36 +664,43 @@ comments: true
```cpp title="binary_search_tree.cpp"
/* 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);
@@ -678,8 +711,9 @@ comments: true
}
/* 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;