feat: leetcode 669

deweyou · deweyou · commit ba31a607f622 · 2022-09-10T11:24:17.000+08:00
diff --git a/README.md b/README.md
@@ -2,7 +2,7 @@
 
 <p align="center">
 <!-- TOPICS COUNT START -->
-<img src="https://img.shields.io/badge/-进度:489-green" alt="进度:489">
+<img src="https://img.shields.io/badge/-进度:490-green" alt="进度:490">
 <!-- TOPICS COUNT END -->
 <a href="./assets/docs/TOPICS.md"><img src="https://img.shields.io/badge/-题库目录-blue" alt="题库目录"></a>
 <a href="./assets/docs/CATEGORIES.md"><img src="https://img.shields.io/badge/-题库分类-red" alt="题库分类"></a>
diff --git a/assets/data/categories.json b/assets/data/categories.json
@@ -3236,6 +3236,12 @@
         "path": "./problemset/maximum-width-of-binary-tree/README.md",
         "difficulty": "中等"
       },
+      {
+        "id": "669",
+        "title": "修剪二叉搜索树",
+        "path": "./problemset/trim-a-binary-search-tree/README.md",
+        "difficulty": "中等"
+      },
       {
         "id": "675",
         "title": "为高尔夫比赛砍树",
@@ -3825,6 +3831,12 @@
         "path": "./problemset/maximum-width-of-binary-tree/README.md",
         "difficulty": "中等"
       },
+      {
+        "id": "669",
+        "title": "修剪二叉搜索树",
+        "path": "./problemset/trim-a-binary-search-tree/README.md",
+        "difficulty": "中等"
+      },
       {
         "id": "687",
         "title": "最长同值路径",
diff --git a/assets/data/topics.json b/assets/data/topics.json
@@ -3399,6 +3399,16 @@
     "url": "https://leetcode.cn/problems/kth-smallest-number-in-multiplication-table/",
     "path": "./problemset/kth-smallest-number-in-multiplication-table/README.md"
   },
+  {
+    "id": "669",
+    "title": {
+      "cn": "修剪二叉搜索树",
+      "en": "trim-a-binary-search-tree"
+    },
+    "difficulty": "中等",
+    "url": "https://leetcode.cn/problems/trim-a-binary-search-tree/",
+    "path": "./problemset/trim-a-binary-search-tree/README.md"
+  },
   {
     "id": "675",
     "title": {
diff --git a/assets/docs/CATEGORIES.md b/assets/docs/CATEGORIES.md
@@ -593,6 +593,7 @@
 | 654. [最大二叉树](../../problemset/maximum-binary-tree/README.md) | 中等 |
 | 655. [输出二叉树](../../problemset/print-binary-tree/README.md) | 中等 |
 | 662. [二叉树最大宽度](../../problemset/maximum-width-of-binary-tree/README.md) | 中等 |
+| 669. [修剪二叉搜索树](../../problemset/trim-a-binary-search-tree/README.md) | 中等 |
 | 675. [为高尔夫比赛砍树](../../problemset/cut-off-trees-for-golf-event/README.md) | 困难 |
 | 687. [最长同值路径](../../problemset/longest-univalue-path/README.md) | 中等 |
 | 691. [贴纸拼词](../../problemset/stickers-to-spell-word/README.md) | 困难 |
@@ -712,6 +713,7 @@
 | 654. [最大二叉树](../../problemset/maximum-binary-tree/README.md) | 中等 |
 | 655. [输出二叉树](../../problemset/print-binary-tree/README.md) | 中等 |
 | 662. [二叉树最大宽度](../../problemset/maximum-width-of-binary-tree/README.md) | 中等 |
+| 669. [修剪二叉搜索树](../../problemset/trim-a-binary-search-tree/README.md) | 中等 |
 | 687. [最长同值路径](../../problemset/longest-univalue-path/README.md) | 中等 |
 | 814. [二叉树剪枝](../../problemset/binary-tree-pruning/README.md) | 中等 |
 | 919. [完全二叉树插入器](../../problemset/complete-binary-tree-inserter/README.md) | 中等 |
diff --git a/assets/docs/TOPICS.md b/assets/docs/TOPICS.md
@@ -680,6 +680,8 @@
 
 [668. 乘法表中第k小的数](../../problemset/kth-smallest-number-in-multiplication-table/README.md)
 
+[669. 修剪二叉搜索树](../../problemset/trim-a-binary-search-tree/README.md)
+
 [675. 为高尔夫比赛砍树](../../problemset/cut-off-trees-for-golf-event/README.md)
 
 [676. 实现一个魔法字典](../../problemset/implement-magic-dictionary/README.md)
diff --git a/problemset/trim-a-binary-search-tree/README.md b/problemset/trim-a-binary-search-tree/README.md
@@ -0,0 +1,97 @@
+# 修剪二叉搜索树
+
+> 难度：中等
+>
+> https://leetcode.cn/problems/trim-a-binary-search-tree/
+
+## 题目
+
+给你二叉搜索树的根节点 `root` ，同时给定最小边界 `low` 和最大边界 `high`。通过修剪二叉搜索树，使得所有节点的值在`[low, high]`中。修剪树 **不应该** 改变保留在树中的元素的相对结构 (即，如果没有被移除，原有的父代子代关系都应当保留)。 可以证明，存在 **唯一的答案** 。
+
+所以结果应当返回修剪好的二叉搜索树的新的根节点。注意，根节点可能会根据给定的边界发生改变。
+
+### 示例
+
+#### 示例 1：
+
+![image](https://user-images.githubusercontent.com/54696834/189466720-dfdd5148-0e82-4d1c-a308-9859e604f863.png)
+
+```
+输入：root = [1,0,2], low = 1, high = 2
+输出：[1,null,2]
+```
+
+#### 示例 2：
+
+![image](https://user-images.githubusercontent.com/54696834/189466724-aa1cca80-66e4-4711-84eb-f708eb7d3cd3.png)
+
+```
+输入：root = [3,0,4,null,2,null,null,1], low = 1, high = 3
+输出：[3,2,null,1]
+```
+
+## 解题
+
+### 递归
+
+```ts 
+/**
+ * 递归
+ * @desc 时间复杂度 O(N)  空间复杂度 O(N)
+ * @param root
+ * @param low
+ * @param high
+ * @returns
+ */
+export function trimBST(root: TreeNode | null, low: number, high: number): TreeNode | null {
+  if (!root) return null
+
+  if (root.val < low) {
+    return trimBST(root.right, low, high)
+  }
+  else if (root.val > high) {
+    return trimBST(root.left, low, high)
+  }
+  else {
+    root.left = trimBST(root.left, low, high)
+    root.right = trimBST(root.right, low, high)
+    return root
+  }
+}
+```
+
+### 迭代
+
+```ts 
+/**
+ * 迭代
+ * @desc 时间复杂度 O(N)  空间复杂度 O(N)
+ * @param root
+ * @param low
+ * @param high
+ * @returns
+ */
+export function trimBST2(root: TreeNode | null, low: number, high: number): TreeNode | null {
+  while (root && (root.val < low || root.val > high)) {
+    if (root.val < low) root = root.right
+    else root = root.left
+  }
+  if (!root) return null
+
+  for (let node = root; node.left;) {
+    if (node.left.val < low)
+      node.left = node.left.right
+
+    else
+      node = node.left
+  }
+  for (let node = root; node.right;) {
+    if (node.right.val > high)
+      node.right = node.right.left
+
+    else
+      node = node.right
+  }
+  return root
+}
+```
diff --git a/problemset/trim-a-binary-search-tree/index.spec.ts b/problemset/trim-a-binary-search-tree/index.spec.ts
@@ -0,0 +1,22 @@
+import { describe, expect, it } from 'vitest'
+import { trimBST, trimBST2 } from '.'
+import type { TreeNode } from '~/utils/treeNode'
+import { createTreeNode } from '~/utils/treeNode'
+
+describe('修剪二叉搜索树', () => {
+  describe('递归', () => testCase(trimBST))
+  describe('迭代', () => testCase(trimBST2))
+})
+
+function testCase(fn: (root: TreeNode | null, low: number, high: number) => TreeNode | null) {
+  it.each([
+    [
+      [1, 0, 2], 1, 2, [1, null, 2],
+    ],
+    [
+      [3, 0, 4, null, 2, null, null, 1], 1, 3, [3, 2, null, 1],
+    ],
+  ])('示例%#', (root, low, high, expected) => {
+    expect(fn(createTreeNode(root), low, high)).toStrictEqual(createTreeNode(expected))
+  })
+}
diff --git a/problemset/trim-a-binary-search-tree/index.ts b/problemset/trim-a-binary-search-tree/index.ts
@@ -0,0 +1,57 @@
+import type { TreeNode } from '~/utils/treeNode'
+
+/**
+ * 递归
+ * @desc 时间复杂度 O(N)  空间复杂度 O(N)
+ * @param root
+ * @param low
+ * @param high
+ * @returns
+ */
+export function trimBST(root: TreeNode | null, low: number, high: number): TreeNode | null {
+  if (!root) return null
+
+  if (root.val < low) {
+    return trimBST(root.right, low, high)
+  }
+  else if (root.val > high) {
+    return trimBST(root.left, low, high)
+  }
+  else {
+    root.left = trimBST(root.left, low, high)
+    root.right = trimBST(root.right, low, high)
+    return root
+  }
+}
+
+/**
+ * 迭代
+ * @desc 时间复杂度 O(N)  空间复杂度 O(N)
+ * @param root
+ * @param low
+ * @param high
+ * @returns
+ */
+export function trimBST2(root: TreeNode | null, low: number, high: number): TreeNode | null {
+  while (root && (root.val < low || root.val > high)) {
+    if (root.val < low) root = root.right
+    else root = root.left
+  }
+  if (!root) return null
+
+  for (let node = root; node.left;) {
+    if (node.left.val < low)
+      node.left = node.left.right
+
+    else
+      node = node.left
+  }
+  for (let node = root; node.right;) {
+    if (node.right.val > high)
+      node.right = node.right.left
+
+    else
+      node = node.right
+  }
+  return root
+}
