Add solution and test-cases for problem 2176

Author: 0xff-dev

leetcode/2101-2200/2176.Count-Equal-and-Divisible-Pairs-in-an-Array/README.md

@@ -1,28 +1,28 @@
 # [2176.Count Equal and Divisible Pairs in an Array][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
+Given a **0-indexed** integer array `nums` of length n and an integer `k`, return the **number of pairs** `(i, j)` where `0 <= i < j < n`, such that `nums[i] == nums[j]` and `(i * j)` is divisible by `k`.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: nums = [3,1,2,2,2,1,3], k = 2
+Output: 4
+Explanation:
+There are 4 pairs that meet all the requirements:
+- nums[0] == nums[6], and 0 * 6 == 0, which is divisible by 2.
+- nums[2] == nums[3], and 2 * 3 == 6, which is divisible by 2.
+- nums[2] == nums[4], and 2 * 4 == 8, which is divisible by 2.
+- nums[3] == nums[4], and 3 * 4 == 12, which is divisible by 2.
 ```
 
-## 题意
-> ...
-
-## 题解
+**Example 2:**
 
-### 思路1
-> ...
-Count Equal and Divisible Pairs in an Array
-```go
 ```
-
+Input: nums = [1,2,3,4], k = 1
+Output: 0
+Explanation: Since no value in nums is repeated, there are no pairs (i,j) that meet all the requirements.
+```
 
 ## 结语
 

leetcode/2101-2200/2176.Count-Equal-and-Divisible-Pairs-in-an-Array/Solution.go

@@ -1,5 +1,20 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(nums []int, k int) int {
+	count := make(map[int][]int)
+	for i, n := range nums {
+		count[n] = append(count[n], i)
+	}
+	ans := 0
+	for _, list := range count {
+		l := len(list)
+		for i := 0; i < l-1; i++ {
+			for j := i + 1; j < l; j++ {
+				if (list[i]*list[j])%k == 0 {
+					ans++
+				}
+			}
+		}
+	}
+	return ans
 }

leetcode/2101-2200/2176.Count-Equal-and-Divisible-Pairs-in-an-Array/Solution_test.go

@@ -10,30 +10,30 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		nums   []int
+		k      int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{3, 1, 2, 2, 2, 1, 3}, 2, 4},
+		{"TestCase2", []int{1, 2, 3, 4}, 1, 0},
 	}
 
 	//	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.nums, c.k)
 			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.nums, c.k)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }