Merge pull request #824 from 0xff-dev/2958

Add solution and test-cases for problem 2958

Author: 6boris

leetcode/2901-3000/2958.Length-of-Longest-Subarray-With-at-Most-K-Frequency/README.md

@@ -1,28 +1,42 @@
 # [2958.Length of Longest Subarray With at Most K Frequency][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 an integer array `nums` and an integer `k`.
+
+The **frequency** of an element `x` is the number of times it occurs in an array.
+
+An array is called **good** if the frequency of each element in this array is **less than or equal** to `k`.
+
+Return the length of the **longest good** subarray of `nums`.
+
+A **subarray** is a contiguous non-empty sequence of elements within an array.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: nums = [1,2,3,1,2,3,1,2], k = 2
+Output: 6
+Explanation: The longest possible good subarray is [1,2,3,1,2,3] since the values 1, 2, and 3 occur at most twice in this subarray. Note that the subarrays [2,3,1,2,3,1] and [3,1,2,3,1,2] are also good.
+It can be shown that there are no good subarrays with length more than 6.
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Length of Longest Subarray With at Most K Frequency
-```go
 ```
+Input: nums = [1,2,1,2,1,2,1,2], k = 1
+Output: 2
+Explanation: The longest possible good subarray is [1,2] since the values 1 and 2 occur at most once in this subarray. Note that the subarray [2,1] is also good.
+It can be shown that there are no good subarrays with length more than 2.
+```
+
+**Example 3:**
 
+```
+Input: nums = [5,5,5,5,5,5,5], k = 4
+Output: 4
+Explanation: The longest possible good subarray is [5,5,5,5] since the value 5 occurs 4 times in this subarray.
+It can be shown that there are no good subarrays with length more than 4.
+```
 
 ## 结语
 

leetcode/2901-3000/2958.Length-of-Longest-Subarray-With-at-Most-K-Frequency/Solution.go

@@ -1,5 +1,22 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(nums []int, k int) int {
+	start, end := 0, 0
+	ans := 1
+	length := len(nums)
+	count := make(map[int]int)
+	for ; end < length; end++ {
+		count[nums[end]]++
+		if count[nums[end]] <= k {
+			if r := end - start + 1; r > ans {
+				ans = r
+			}
+			continue
+		}
+		for count[nums[end]] > k {
+			start++
+			count[nums[start-1]]--
+		}
+	}
+	return ans
 }

leetcode/2901-3000/2958.Length-of-Longest-Subarray-With-at-Most-K-Frequency/Solution_test.go

@@ -10,30 +10,31 @@ 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{1, 2, 3, 1, 2, 3, 1, 2}, 2, 6},
+		{"TestCase2", []int{1, 2, 1, 2, 1, 2, 1, 2}, 1, 2},
+		{"TestCase3", []int{5, 5, 5, 5, 5, 5, 5}, 4, 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() {
 }