feat: leetcode 515

Author: deweyou

README.md

@@ -2,7 +2,7 @@
 
 <p align="center">
 <!-- TOPICS COUNT START -->
-<img src="https://img.shields.io/badge/-进度:411-green" alt="进度:411">
+<img src="https://img.shields.io/badge/-进度:412-green" alt="进度:412">
 <!-- 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>

assets/data/categories.json

@@ -2774,6 +2774,12 @@
         "path": "./problemset/find-bottom-left-tree-value/README.md",
         "difficulty": "中等"
       },
+      {
+        "id": "515",
+        "title": "在每个树行中找最大值",
+        "path": "./problemset/find-largest-value-in-each-tree-row/README.md",
+        "difficulty": "中等"
+      },
       {
         "id": "589",
         "title": "N 叉树的前序遍历",
@@ -3255,6 +3261,12 @@
         "path": "./problemset/find-bottom-left-tree-value/README.md",
         "difficulty": "中等"
       },
+      {
+        "id": "515",
+        "title": "在每个树行中找最大值",
+        "path": "./problemset/find-largest-value-in-each-tree-row/README.md",
+        "difficulty": "中等"
+      },
       {
         "id": "589",
         "title": "N 叉树的前序遍历",

assets/data/topics.json

@@ -3009,6 +3009,16 @@
     "url": "https://leetcode.cn/problems/find-bottom-left-tree-value/",
     "path": "./problemset/find-bottom-left-tree-value/README.md"
   },
+  {
+    "id": "515",
+    "title": {
+      "cn": "在每个树行中找最大值",
+      "en": "find-largest-value-in-each-tree-row"
+    },
+    "difficulty": "中等",
+    "url": "https://leetcode.cn/problems/find-largest-value-in-each-tree-row/",
+    "path": "./problemset/find-largest-value-in-each-tree-row/README.md"
+  },
   {
     "id": "521",
     "title": {

assets/docs/CATEGORIES.md

@@ -516,6 +516,7 @@
 | 464. [我能赢吗](../../problemset/can-i-win/README.md) | 中等 |
 | 508. [出现次数最多的子树元素和](../../problemset/most-frequent-subtree-sum/README.md) | 中等 |
 | 513. [找树左下角的值](../../problemset/find-bottom-left-tree-value/README.md) | 中等 |
+| 515. [在每个树行中找最大值](../../problemset/find-largest-value-in-each-tree-row/README.md) | 中等 |
 | 589. [N 叉树的前序遍历](../../problemset/n-ary-tree-preorder-traversal/README.md) | 简单 |
 | 590. [N 叉树的后序遍历](../../problemset/n-ary-tree-postorder-traversal/README.md) | 简单 |
 | 606. [根据二叉树创建字符串](../../problemset/construct-string-from-binary-tree/README.md) | 简单 |
@@ -617,6 +618,7 @@
 | 450. [删除二叉搜索树中的节点](../../problemset/delete-node-in-a-bst/README.md) | 中等 |
 | 508. [出现次数最多的子树元素和](../../problemset/most-frequent-subtree-sum/README.md) | 中等 |
 | 513. [找树左下角的值](../../problemset/find-bottom-left-tree-value/README.md) | 中等 |
+| 515. [在每个树行中找最大值](../../problemset/find-largest-value-in-each-tree-row/README.md) | 中等 |
 | 589. [N 叉树的前序遍历](../../problemset/n-ary-tree-preorder-traversal/README.md) | 简单 |
 | 606. [根据二叉树创建字符串](../../problemset/construct-string-from-binary-tree/README.md) | 简单 |
 | 653. [两数之和 IV - 输入 BST](../../problemset/two-sum-iv-input-is-a-bst/README.md) | 简单 |

assets/docs/TOPICS.md

@@ -602,6 +602,8 @@
 
 [513. 找树左下角的值](../../problemset/find-bottom-left-tree-value/README.md)
 
+[515. 在每个树行中找最大值](../../problemset/find-largest-value-in-each-tree-row/README.md)
+
 [521. 最长特殊序列](../../problemset/longest-uncommon-subsequence/README.md)
 
 [532. 数组中的 k-diff 数对](../../problemset/k-diff-pairs-in-an-array/README.md)

problemset/find-largest-value-in-each-tree-row/README.md

@@ -0,0 +1,59 @@
+# 在每个树行中找最大值
+
+> 难度：中等
+>
+> https://leetcode.cn/problems/find-largest-value-in-each-tree-row/
+
+## 题目
+
+给定一棵二叉树的根节点 `root` ，请找出该二叉树中每一层的最大值。
+
+### 示例 
+
+#### 示例 1：
+
+![image](https://user-images.githubusercontent.com/54696834/175475977-a1e1956a-b6a7-43da-949d-8422ee855673.png)
+
+```
+输入: root = [1,3,2,5,3,null,9]
+输出: [1,3,9]
+```
+
+#### 示例 2：
+
+```
+输入: root = [1,2,3]
+输出: [1,3]
+```
+
+## 解题
+
+```ts 
+/**
+ * 广度优先搜索
+ * @desc 时间复杂度 O(N)  空间复杂度 O(N)
+ * @param root
+ * @returns
+ */
+export function largestValues(root: TreeNode | null): number[] {
+  const ans: number[] = []
+
+  if (root) {
+    const queue: TreeNode[] = [root]
+
+    while (queue.length) {
+      let len = queue.length
+      let maxVal = -Number.MAX_VALUE
+      while (len--) {
+        const node = queue.pop()!
+        maxVal = Math.max(maxVal, node.val)
+        node.left && queue.unshift(node.left)
+        node.right && queue.unshift(node.right)
+      }
+      ans.push(maxVal)
+    }
+  }
+
+  return ans
+}
+```

problemset/find-largest-value-in-each-tree-row/index.spec.ts

@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest'
+import { largestValues } from '.'
+import type { TreeNode } from '~/utils/treeNode'
+import { createTreeNode } from '~/utils/treeNode'
+
+describe('在每个树行中找最大值', () => {
+  testCase(largestValues)
+})
+
+function testCase(fn: (root: TreeNode | null) => number[]) {
+  it.each([
+    [
+      [1, 3, 2, 5, 3, null, 9],
+      [1, 3, 9],
+    ],
+    [
+      [1, 2, 3],
+      [1, 3],
+    ],
+  ])('示例%#', (root, expected) => {
+    expect(fn(createTreeNode(root))).toStrictEqual(expected)
+  })
+}

problemset/find-largest-value-in-each-tree-row/index.ts

@@ -0,0 +1,29 @@
+import type { TreeNode } from '~/utils/treeNode'
+
+/**
+ * 广度优先搜索
+ * @desc 时间复杂度 O(N)  空间复杂度 O(N)
+ * @param root
+ * @returns
+ */
+export function largestValues(root: TreeNode | null): number[] {
+  const ans: number[] = []
+
+  if (root) {
+    const queue: TreeNode[] = [root]
+
+    while (queue.length) {
+      let len = queue.length
+      let maxVal = -Number.MAX_VALUE
+      while (len--) {
+        const node = queue.pop()!
+        maxVal = Math.max(maxVal, node.val)
+        node.left && queue.unshift(node.left)
+        node.right && queue.unshift(node.right)
+      }
+      ans.push(maxVal)
+    }
+  }
+
+  return ans
+}