Add solution and test-cases for problem 2501

leetcode/2501-2600/2501.Longest-Square-Streak-in-an-Array/README.md

@@ -0,0 +1,38 @@
+# [2501.Longest Square Streak in an Array][title]
+
+## Description
+You are given an integer array `nums`. A subsequence of `nums` is called a **square streak** if:
+
+- The length of the subsequence is at least `2`, and
+- **after** sorting the subsequence, each element (except the first element) is the **square** of the previous number.
+
+Return the length of the **longest square streak** in `nums`, or return `-1` if there is no **square streak**.
+
+A **subsequence** is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.
+
+**Example 1:**
+
+```
+Input: nums = [4,3,6,16,8,2]
+Output: 3
+Explanation: Choose the subsequence [4,16,2]. After sorting it, it becomes [2,4,16].
+- 4 = 2 * 2.
+- 16 = 4 * 4.
+Therefore, [4,16,2] is a square streak.
+It can be shown that every subsequence of length 4 is not a square streak.
+```
+
+**Example 2:**
+
+```
+Input: nums = [2,3,5,6,7]
+Output: -1
+Explanation: There is no square streak in nums so return -1.
+```
+
+## 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/longest-square-streak-in-an-array
+[me]: https://github.com/kylesliu/awesome-golang-algorithm

leetcode/2501-2600/2501.Longest-Square-Streak-in-an-Array/Solution.go

@@ -1,5 +1,32 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "sort"
+
+func isPerfectSquare(num int) int {
+	for i := 1; i*i <= num; i++ {
+		if i*i == num {
+			return i
+		}
+	}
+	return -1
+}
+
+func Solution(nums []int) int {
+	sort.Ints(nums)
+	ans := -1
+	pre := make(map[int]int)
+	for _, n := range nums {
+		pre[n] = 1
+	}
+	for _, n := range nums {
+		i := isPerfectSquare(n)
+		if i == -1 {
+			continue
+		}
+		if l, ok := pre[i]; ok {
+			pre[n] = l + 1
+			ans = max(ans, pre[n])
+		}
+	}
+	return ans
 }

leetcode/2501-2600/2501.Longest-Square-Streak-in-an-Array/Solution_test.go

@@ -10,12 +10,11 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs []int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{4, 3, 6, 16, 8, 2}, 3},
+		{"TestCase2", []int{2, 3, 5, 6, 7}, -1},
 	}
 
 	//	开始测试
@@ -30,10 +29,10 @@ func TestSolution(t *testing.T) {
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }