Add solution and test-cases for problem 2537

Author: 0xff-dev

leetcode/2501-2600/2537.Count-the-Number-of-Good-Subarrays/README.md

@@ -0,0 +1,35 @@
+# [2537.Count the Number of Good Subarrays][title]
+
+## Description
+Given an integer array `nums` and an integer `k`, return the number of **good** subarrays of `nums`.
+
+A subarray `arr` is **good** if there are **at least** `k` pairs of indices `(i, j)` such that `i < j` and `arr[i] == arr[j]`.
+
+A **subarray** is a contiguous **non-empty** sequence of elements within an array.
+
+**Example 1:**
+
+```
+Input: nums = [1,1,1,1,1], k = 10
+Output: 1
+Explanation: The only good subarray is the array nums itself.
+```
+
+**Example 2:**
+
+```
+Input: nums = [3,1,4,3,2,2,4], k = 2
+Output: 4
+Explanation: There are 4 different good subarrays:
+- [3,1,4,3,2,2] that has 2 pairs.
+- [3,1,4,3,2,2,4] that has 3 pairs.
+- [1,4,3,2,2,4] that has 2 pairs.
+- [4,3,2,2,4] that has 2 pairs.
+```
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-golang-algorithm][me]
+
+[title]: https://leetcode.com/problems/count-the-number-of-good-subarrays
+[me]: https://github.com/kylesliu/awesome-golang-algorithm

leetcode/2501-2600/2537.Count-the-Number-of-Good-Subarrays/Solution.go

@@ -1,5 +1,24 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(nums []int, k int) int64 {
+	l := len(nums)
+	count := make(map[int]int64)
+	start, end := 0, 0
+
+	var (
+		ans, pairs int64
+	)
+
+	i64k := int64(k)
+	for ; end < l; end++ {
+		pairs += count[nums[end]]
+		count[nums[end]]++
+
+		for ; start < end && pairs >= i64k; start++ {
+			ans += int64(l - end)
+			count[nums[start]]--
+			pairs -= count[nums[start]]
+		}
+	}
+	return ans
 }

leetcode/2501-2600/2537.Count-the-Number-of-Good-Subarrays/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 int64
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{1, 1, 1, 1, 1}, 10, 1},
+		{"TestCase2", []int{3, 1, 4, 3, 2, 2, 4}, 2, 4},
 	}
 
 	//	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() {
 }