Add solution and test-cases for problem 2928

leetcode/2901-3000/2928.Distribute-Candies-Among-Children-I/README.md

@@ -1,28 +1,25 @@
 # [2928.Distribute Candies Among Children I][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
+You are given two positive integers `n` and `limit`.
+
+Return the **total number** of ways to distribute `n` candies among `3` children such that no child gets more than `limit` candies.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: n = 5, limit = 2
+Output: 3
+Explanation: There are 3 ways to distribute 5 candies such that no child gets more than 2 candies: (1, 2, 2), (2, 1, 2) and (2, 2, 1).
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Distribute Candies Among Children I
-```go
 ```
-
+Input: n = 3, limit = 3
+Output: 10
+Explanation: There are 10 ways to distribute 3 candies such that no child gets more than 3 candies: (0, 0, 3), (0, 1, 2), (0, 2, 1), (0, 3, 0), (1, 0, 2), (1, 1, 1), (1, 2, 0), (2, 0, 1), (2, 1, 0) and (3, 0, 0).
+```
 
 ## 结语
 

leetcode/2901-3000/2928.Distribute-Candies-Among-Children-I/Solution.go

@@ -1,5 +1,30 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func binom(a, b int) int {
+	n, k := a, b
+	if n < 0 || k < 0 || n < k {
+		return 0
+	}
+	if k > n-k {
+		k = n - k
+	}
+	var result int = 1
+	for i := 1; i <= k; i++ {
+		result = result * (n - i + 1) / i
+	}
+	return result
+}
+
+func Solution(n int, limit int) int {
+	total := binom(n+2, 2)
+
+	n1 := n - (limit + 1)
+	n2 := n - 2*(limit+1)
+	n3 := n - 3*(limit+1)
+
+	total -= 3 * binom(n1+2, 2)
+	total += 3 * binom(n2+2, 2)
+	total -= binom(n3+2, 2)
+
+	return total
 }

leetcode/2901-3000/2928.Distribute-Candies-Among-Children-I/Solution_test.go

@@ -9,31 +9,30 @@ import (
 func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
-		name   string
-		inputs bool
-		expect bool
+		name     string
+		n, limit int
+		expect   int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", 5, 2, 3},
+		{"TestCase2", 3, 3, 10},
 	}
 
 	//	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.n, c.limit)
 			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.n, c.limit)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }