[#1782] feat(MaxAverageRatio): Add priority queue method

leetcode_helper.sh

@@ -337,9 +337,9 @@ EOF
     # 建立 C# 專案
     mkdir -p "$problem_dir/csharp"
     cd "$problem_dir/csharp"
-    dotnet new console -n "Problem$number" --force > /dev/null 2>&1
+    dotnet new console --force > /dev/null 2>&1
     
-    # 建立 C# 解法檔案
+    # 覆寫自動生成的 Program.cs
     cat > "Program.cs" << EOF
 // LeetCode $number: $(echo "$name" | tr '-' ' ' | sed 's/\b\w/\u&/g')
 // 難度: $difficulty
@@ -430,7 +430,7 @@ EOF
     echo "├── README.md"
     echo "├── csharp/"
     echo "│   ├── Program.cs"
-    echo "│   └── Problem$number.csproj"
+    echo "│   └── *.csproj"
     echo "├── go/"
     echo "│   ├── main.go"
     echo "│   └── go.mod"

logs/2025-09.md

@@ -0,0 +1,69 @@
+# 2025-09 學習記錄
+
+## 📅 每日練習記錄
+
+### Week 1
+| 日期 | 題目 | 難度 | 語言 | 耗時 | 狀態 | 心得 |
+|------|------|------|------|------|------|------|
+| 09-01 | Maximum Average Pass Ratio | Medium | C# | 1hr | Done | 第一次用到Priority Queue |
+
+### Week 2  
+| 日期 | 題目 | 難度 | 語言 | 耗時 | 狀態 | 心得 |
+|------|------|------|------|------|------|------|
+| | | | | | | |
+
+### Week 3
+| 日期 | 題目 | 難度 | 語言 | 耗時 | 狀態 | 心得 |
+|------|------|------|------|------|------|------|
+| | | | | | | |
+
+### Week 4
+| 日期 | 題目 | 難度 | 語言 | 耗時 | 狀態 | 心得 |
+|------|------|------|------|------|------|------|
+| | | | | | | |
+
+## 📈 本月統計
+
+### 完成情況
+- **總練習天數**: 1 天
+- **完成題數**: 1題
+- **語言分布**: C# 1(題), Go 0(題)
+- **難度分布**: Easy 0(題), Medium 1(題), Hard 0(題)
+
+### 時間投入
+- **總時間**: 1小時
+- **平均每題**: 分鐘
+- **每日平均**: 分鐘
+
+## 🎯 本月重點學習
+
+### 新掌握的技巧
+1. 貪心策略
+
+### 常犯錯誤分析
+1. 
+
+### 語言學習心得
+- **C#**: 
+- **Go**: 
+
+## 🔄 遇到的困難與解決
+
+### 困難1: 
+- **問題**: 
+- **解決**: 
+- **學習**: 
+
+## 📝 改進計畫
+
+### 下月目標
+1. 
+
+### 學習方法調整
+1. 
+
+## 💡 本月金句
+> 
+
+---
+**總結**: 

problems/1792-maximum-average-pass-ratio/README.md

@@ -0,0 +1,75 @@
+# [1792] Maximum Average Pass Ratio
+
+## 題目資訊
+- **難度**: Medium
+- **標籤**: Array, Greedy, Heap(Priority Queue)
+- **題目連結**: [LeetCode](https://leetcode.com/problems/maximum-average-pass-ratio/)
+- **練習日期**: 2025-09-01
+
+## 題目描述
+There is a school that has classes of students and each class will be having a final exam. You are given a 2D integer array `classes`, where `classes[i] = [passi, totali]`. You know beforehand that in the `ith` class, there are `totali` total students, but only `passi` number of students will pass the exam.
+
+You are also given an integer `extraStudents`. There are another `extraStudents` brilliant students that are **guaranteed** to pass the exam of any class they are assigned to. You want to assign each of the `extraStudents` students to a class in a way that **maximizes** the **average** pass ratio across **all** the classes.
+
+The **pass ratio** of a class is equal to the number of students of the class that will pass the exam divided by the total number of students of the class. The **average pass ratio** is the sum of pass ratios of all the classes divided by the number of the classes.
+
+Return the *maximum* possible average pass ratio after assigning the `extraStudents` students. Answers within `10-5` of the actual answer will be accepted.
+
+## 解題思路
+
+### 初步分析
+- 這題主要考察什麼概念?
+   - 貪心算法，找出每次分配學生，通過率可以提升至最高
+- Pass Ratio = pass / total
+- Average Pass Ratio = sum of pass ration / number of class
+
+### 解法概述
+1. **暴力解法**: 
+   - 思路：
+      - 每次分配一個學生看哪個班級提升率會最高
+      - leetcode 這邊會 time limit exceeded
+   - 時間複雜度：O(N)
+   - 空間複雜度：O(N)
+   
+2. **最佳解法**: 
+   - 思路：
+      - Priority Queue(Max Heap) 存每個班級潛在
+   - 時間複雜度：O(?)
+   - 空間複雜度：O(?)
+
+## 測試案例
+
+### 範例輸入輸出
+```
+Input: classes = [[1,2],[3,5],[2,2]], extraStudents = 2
+Output: 0.78333
+Explanation: You can assign the two extra students to the first class. The average pass ratio will be equal to (3/4 + 3/5 + 2/2) / 3 = 0.78333.
+```
+
+### 邊界情況
+- 1 <= classes.length <= 10^5
+- classes[i].length == 2
+- 1 <= passi <= totali <= 10^5
+- 1 <= extraStudents <= 10^5
+
+## 學習筆記
+
+### 今天學到什麼？
+- 第一次使用 Priority Queue
+- 第一次使用 Unit Test
+
+### 遇到的困難
+- 可能要再了解 Priority Queue 更多實際用途
+
+### 改善方向
+- 
+
+### 相關題目
+- [#1627](https://leetcode.com/problems/graph-connectivity-with-threshold/description/) Graph Connectivity With Threshold
+- [#1728](https://leetcode.com/problems/cat-and-mouse-ii/description/) Cat and Mouse II
+- [#3440](https://leetcode.com/problems/reschedule-meetings-for-maximum-free-time-ii/description/) Reschedule Meetings for Maximum Free Time II
+
+---
+**總結**:
+1. 貪心策略，每次都選擇當下收益最大解
+2. 練習使用Priority Queue 快速找到最大收益

problems/1792-maximum-average-pass-ratio/csharp/Program.cs

@@ -0,0 +1,187 @@
+// LeetCode 1792: Maximum Average Pass Ratio
+// 難度: Medium
+// 日期: 2025-09-01
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+public class Solution
+{
+    public double MaxAverageRatio(int[][] classes, int extraStudents)
+    {
+        // use priority queue
+        var pq = new PriorityQueue<ClassInfo, double>();
+
+        // 初始化：將所有班級加入優先佇列 
+        for (int i = 0; i < classes.Length; i++)
+        {
+            int pass = classes[i][0];
+            int total = classes[i][1];
+
+            double gain = CalculateGain(pass, total);
+
+            pq.Enqueue(new ClassInfo(pass, total), -gain);
+        }
+
+        for (int i = 0; i < extraStudents; i++)
+        {
+            var classInfo = pq.Dequeue();
+
+            classInfo.Pass++;
+            classInfo.Total++;
+
+            double newGain = CalculateGain(classInfo.Pass, classInfo.Total);
+            pq.Enqueue(classInfo, -newGain);
+        }
+
+        double totalRatio = 0;
+        while (pq.Count > 0)
+        {
+            var classInfo = pq.Dequeue();
+            totalRatio += (double)classInfo.Pass / classInfo.Total;
+        }
+
+        return totalRatio / classes.Length;
+    }
+
+    public double MaxAverageRatioByBruteForce(int[][] classes, int extraStudents)
+    {
+        var n = classes.Length;
+        var pass = new int[n];
+        var total = new int[n];
+
+        for (var i = 0; i < n; i++)
+        {
+            pass[i] = classes[i][0];
+            total[i] = classes[i][1];
+        }
+
+        for (int student = 0; student < extraStudents; student++)
+        {
+            int bestClass = -1;
+            double maxInprovement = 0;
+
+            for (int i = 0; i < n; i++)
+            {
+                double currentAvg = CalculateAvergaeRatio(pass, total);
+
+                pass[i]++;
+                total[i]++;
+
+                double newAvg = CalculateAvergaeRatio(pass, total);
+                double improvement = newAvg - currentAvg;
+
+                pass[i]--;
+                total[i]--;
+
+                if (improvement > maxInprovement)
+                {
+                    maxInprovement = improvement;
+                    bestClass = i;
+                }
+            }
+
+            if (bestClass != -1)
+            {
+                pass[bestClass]++;
+                total[bestClass]++;
+            }
+        }
+
+        return CalculateAvergaeRatio(pass, total);
+    }
+
+    private double CalculateGain(int pass, int total)
+    {
+        // 計算提升率
+        return (double)(pass + 1) / (total + 1) - (double)pass / total;
+    }
+
+    private double CalculateAvergaeRatio(int[] pass, int[] total)
+    {
+        double sum = 0;
+        for (var i = 0; i < pass.Length; i++)
+        {
+            sum += (double)pass[i] / total[i];
+        }
+        return sum / pass.Length;
+    }
+}
+
+public class ClassInfo
+{
+    public int Pass { get; set; }
+    public int Total { get; set; }
+
+    public ClassInfo(int pass, int total)
+    {
+        Pass = pass;
+        Total = total;
+    }
+}
+
+// 測試程式
+public class Program
+{
+    public static void Main()
+    {
+        Solution solution = new Solution();
+
+        // TestCase
+        TestCase1(solution);
+        TestCase2(solution);
+    }
+
+    static void TestCase1(Solution solution)
+    {
+        // Input: 
+        int[][] classes = new int[][]
+        {
+            new int[] {1, 2},
+            new int[] {3, 5},
+            new int[] {2, 2}
+        };
+        int extraStudents = 2;
+
+        Console.WriteLine("Test 1: ");
+        Console.WriteLine($"classes: [{string.Join("], [", classes.Select(c => string.Join(", ", c)))}]");
+        Console.WriteLine($"extraStudents: {extraStudents}");
+
+        // Expected: 
+        Console.WriteLine("Expect: ");
+        Console.WriteLine($"output: 0.78333");
+
+        // Actual: 
+        Console.WriteLine("Actual: ");
+        Console.WriteLine($"Brute Force: {solution.MaxAverageRatioByBruteForce(classes, extraStudents):F6}");
+        Console.WriteLine($"Priority Queue: {solution.MaxAverageRatio(classes, extraStudents):F6}");
+    }
+
+
+    static void TestCase2(Solution solution)
+    {
+        // Input: 
+        int[][] classes = new int[][]
+        {
+            new int[] {2, 4},
+            new int[] {3, 9},
+            new int[] {4, 5},
+            new int[] {2, 10}
+        };
+        int extraStudents = 4;
+
+        Console.WriteLine("Test 2: ");
+        Console.WriteLine($"classes: [{string.Join("], [", classes.Select(c => string.Join(", ", c)))}]");
+        Console.WriteLine($"extraStudents: {extraStudents}");
+
+        // Expected: 
+        Console.WriteLine("Expect: ");
+        Console.WriteLine($"output: 0.53485");
+
+        // Actual: 
+        Console.WriteLine("Actual: ");
+        Console.WriteLine($"Brute Force: {solution.MaxAverageRatioByBruteForce(classes, extraStudents):F6}");
+        Console.WriteLine($"Priority Queue: {solution.MaxAverageRatio(classes, extraStudents):F6}");
+    }
+}

problems/1792-maximum-average-pass-ratio/csharp/csharp.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

problems/1792-maximum-average-pass-ratio/test/SolutionTests.cs

@@ -0,0 +1,176 @@
+// LeetCode 1792 單元測試
+// 使用 xUnit 框架
+
+using Xunit;
+using System;
+using System.Collections.Generic;
+
+public class SolutionTests
+{
+    private readonly Solution _solution;
+    private const double TOLERANCE = 0.00001;
+
+    public SolutionTests()
+    {
+        _solution = new Solution();
+    }
+
+    #region Basic Test
+    [Fact]
+    public void TestCase1()
+    {
+        // Arrange
+        int[][] classes = new int[][]
+        {
+            new int[] {1, 2},
+            new int[] {3, 5},
+            new int[] {2, 2}
+        };
+        int extraStudents = 2;
+        double expected = 0.78333;
+
+        // Act
+        var result = _solution.MaxAverageRatio(classes, extraStudents);
+
+        // Assert
+        Assert.True(Math.Abs(result - expected) < TOLERANCE,
+            $"Expected: {expected}, Actual: {result}");
+    }
+
+    [Fact]
+    public void TestCase2()
+    {
+
+        // Arrange
+        int[][] classes = new int[][]
+        {
+            new int[] {2, 4},   // 通過率: 2/4 = 0.5
+            new int[] {3, 9},   // 通過率: 3/9 = 0.333...
+            new int[] {4, 5},   // 通過率: 4/5 = 0.8
+            new int[] {2, 10}   // 通過率: 2/10 = 0.2
+        };
+        int extraStudents = 4;
+        double expected = 0.53485;
+
+        // Act
+        var result = _solution.MaxAverageRatio(classes, extraStudents);
+
+        // Assert
+        Assert.True(Math.Abs(result - expected) < TOLERANCE,
+            $"Expected: {expected}, Actual: {result}");
+    }
+
+    [Fact]
+    public void TestBruteForceVsPriorityQueue()
+    {
+        // Arrange
+        int[][] classes = new int[][]
+        {
+            new int[] {1, 3},
+            new int[] {2, 4},
+            new int[] {1, 5}
+        };
+        int extraStudents = 3;
+
+        // Act
+        var resultBruteForce = _solution.MaxAverageRatioByBruteForce(classes, extraStudents);
+        var resultPriorityQueue = _solution.MaxAverageRatio(classes, extraStudents);
+
+        // Assert
+        Assert.True(Math.Abs(resultBruteForce - resultPriorityQueue) < TOLERANCE,
+            $"Brute Force: {resultBruteForce}, Priority Queue: {resultPriorityQueue}");
+    }
+    #endregion
+
+    #region Edge Test
+    [Fact]
+    public void TestEdgeCases_MinClassesLength_OneClass()
+    {
+        // Arrange
+        int[][] classes = new int[][]
+        {
+            new int[] {50, 100}
+        };
+        int extraStudents = 10;
+        double expected = 60.0 / 110.0;
+
+        // Act
+        var result = _solution.MaxAverageRatio(classes, extraStudents);
+
+        // Assert
+        Assert.True(result >= 0 && result <= 1,
+            $"Result should be between 0 and 1, got: {result}");
+        Assert.True(Math.Abs(result - expected) < TOLERANCE,
+            $"Expected: {expected}, Actual: {result}");
+    }
+
+    [Fact]
+    public void TestEdgeCases_LargeClassesLength()
+    {
+        // Arrange
+        const int numClasses = 1000;
+        var classes = new int[numClasses][];
+        var random = new Random(42);
+
+        for (int i = 0; i < numClasses; i++)
+        {
+            int total = random.Next(10, 100);  // total 在 10-100 之間
+            int pass = random.Next(1, total + 1);  // pass 在 1-total 之間
+            classes[i] = new int[] { pass, total };
+        }
+        int extraStudents = 100;
+
+        // Act
+        var result = _solution.MaxAverageRatio(classes, extraStudents);
+
+        // Assert
+        Assert.True(result >= 0 && result <= 1,
+            $"Result should be between 0 and 1, got: {result}");
+    }
+
+    [Fact]
+    public void TestEdgeCases_MinExtraStudents_One()
+    {
+        // Arrange
+        int[][] classes = new int[][]
+        {
+            new int[] {1, 3},
+            new int[] {2, 4}
+        };
+        int extraStudents = 1;
+
+        // Act
+        var result = _solution.MaxAverageRatio(classes, extraStudents);
+
+        // Assert
+        double originalAvg = (1.0 / 3 + 2.0 / 4) / 2;
+        Assert.True(result > originalAvg,
+            $"Result {result} should be greater than original average {originalAvg}");
+    }
+
+    [Fact]
+    public void TestEdgeCases_LargeExtraStudents()
+    {
+        // Arrange - 大量額外學生
+        int[][] classes = new int[][]
+        {
+            new int[] {10, 100},  // 10% 通過率
+            new int[] {20, 100},  // 20% 通過率
+            new int[] {30, 100}   // 30% 通過率
+        };
+        int extraStudents = 10000;
+
+        // Act
+        var result = _solution.MaxAverageRatio(classes, extraStudents);
+
+        // Assert
+        Assert.True(result >= 0 && result <= 1, 
+            $"Result should be between 0 and 1, got: {result}");
+        
+        // 大量學生加入後，通過率應該顯著提升
+        double originalAvg = (0.1 + 0.2 + 0.3) / 3; // = 0.2
+        Assert.True(result > originalAvg + 0.1, 
+            $"Result {result} should be significantly higher than original average {originalAvg}");
+    }
+    #endregion
+}

problems/1792-maximum-average-pass-ratio/test/TestProject.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
+    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="../csharp/csharp.csproj" />
+  </ItemGroup>
+
+</Project>