Add solution and test-cases for problem 1792

Author: 0xff-dev

leetcode/1701-1800/1792.Maximum-Average-Pass-Ratio/README.md

@@ -1,28 +1,28 @@
 # [1792.Maximum Average Pass Ratio][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+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 `extraStudent` 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.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+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.
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Maximum Average Pass Ratio
-```go
 ```
-
+Input: classes = [[2,4],[3,9],[4,5],[2,10]], extraStudents = 4
+Output: 0.53485
+```
 
 ## 结语
 

leetcode/1701-1800/1792.Maximum-Average-Pass-Ratio/Solution.go

@@ -1,5 +1,60 @@
 package Solution
 
-func Solution(x bool) bool {
+import "container/heap"
+
+type heap1792 [][]int
+
+func (h *heap1792) Len() int {
+	return len(*h)
+}
+
+func (h *heap1792) Swap(i, j int) {
+	(*h)[i], (*h)[j] = (*h)[j], (*h)[i]
+}
+
+func (h *heap1792) Less(i, j int) bool {
+	a, b := (*h)[i], (*h)[j]
+	// 判断增幅
+	aa := (float64(a[0]+1) / float64(a[1]+1)) - (float64(a[0]) / float64(a[1]))
+	bb := (float64(b[0]+1) / float64(b[1]+1)) - (float64(b[0]) / float64(b[1]))
+	return aa > bb
+}
+
+func (h *heap1792) Push(x any) {
+	*h = append(*h, x.([]int))
+}
+
+func (h *heap1792) Pop() any {
+	old := *h
+	l := len(old)
+	x := old[l-1]
+	*h = old[:l-1]
 	return x
 }
+
+func Solution(classes [][]int, extraStudents int) float64 {
+	h := &heap1792{}
+	var ans float64 = 0
+	for _, c := range classes {
+		if c[0] == c[1] {
+			// 永远都是1提升不了
+			ans++
+			continue
+		}
+		heap.Push(h, c)
+	}
+	if h.Len() > 0 {
+		for ; extraStudents > 0; extraStudents-- {
+			top := heap.Pop(h).([]int)
+			top[0]++
+			top[1]++
+			heap.Push(h, top)
+		}
+		for h.Len() > 0 {
+			top := heap.Pop(h).([]int)
+			ans += float64(top[0]) / float64(top[1])
+		}
+	}
+
+	return ans / float64(len(classes))
+}

leetcode/1701-1800/1792.Maximum-Average-Pass-Ratio/Solution_test.go

@@ -9,31 +9,31 @@ import (
 func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
-		name   string
-		inputs bool
-		expect bool
+		name          string
+		classes       [][]int
+		extraStudents int
+		expect        float64
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", [][]int{{1, 2}, {3, 5}, {2, 2}}, 2, 0.7833333333333333},
+		{"TestCase2", [][]int{{2, 4}, {3, 9}, {4, 5}, {2, 10}}, 4, 0.5348484848484849},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.classes, c.extraStudents)
 			if !reflect.DeepEqual(got, c.expect) {
-				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v %v",
+					c.expect, got, c.classes, c.extraStudents)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }