Add solution and test-cases for problem 3321

go.mod

@@ -3,6 +3,7 @@ module awesome-golang-algorithm
 go 1.24
 
 require (
+	github.com/emirpasic/gods/v2 v2.0.0-alpha
 	github.com/imroc/req/v3 v3.54.2
 	github.com/stretchr/testify v1.11.1
 )

go.sum

@@ -3,6 +3,8 @@ github.com/andybalholm/brotli v1.2.0/go.mod h1:rzTDkvFWvIrjDXZHkuS16NPggd91W3kUS
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/emirpasic/gods/v2 v2.0.0-alpha h1:dwFlh8pBg1VMOXWGipNMRt8v96dKAIvBehtCt6OtunU=
+github.com/emirpasic/gods/v2 v2.0.0-alpha/go.mod h1:W0y4M2dtBB9U5z3YlghmpuUhiaZT2h6yoeE+C1sCp6A=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/icholy/digest v1.1.0 h1:HfGg9Irj7i+IX1o1QAmPfIBNu/Q5A5Tu3n/MED9k9H4=

leetcode/3301-3400/3321.Find-X-Sum-of-All-K-Long-Subarrays-II/README.md

@@ -1,28 +1,43 @@
 # [3321.Find X-Sum of All K-Long Subarrays II][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 array `nums` of `n` integers and two integers `k` and `x`.
+
+The **x-sum** of an array is calculated by the following procedure:
+
+- Count the occurrences of all elements in the array.
+- Keep only the occurrences of the top `x` most frequent elements. If two elements have the same number of occurrences, the element with the **bigger** value is considered more frequent.
+- Calculate the sum of the resulting array.
+
+**Note** that if an array has less than x distinct elements, its **x-sum** is the sum of the array.
+
+Return an integer array `answer` of length `n - k + 1` where `answer[i]` is the **x-sum** of the subarray `nums[i..i + k - 1]`.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
-```
+Input: nums = [1,1,2,2,3,4,2,3], k = 6, x = 2
 
-## 题意
-> ...
+Output: [6,10,12]
 
-## 题解
+Explanation:
 
-### 思路1
-> ...
-Find X-Sum of All K-Long Subarrays II
-```go
+For subarray [1, 1, 2, 2, 3, 4], only elements 1 and 2 will be kept in the resulting array. Hence, answer[0] = 1 + 1 + 2 + 2.
+For subarray [1, 2, 2, 3, 4, 2], only elements 2 and 4 will be kept in the resulting array. Hence, answer[1] = 2 + 2 + 2 + 4. Note that 4 is kept in the array since it is bigger than 3 and 1 which occur the same number of times.
+For subarray [2, 2, 3, 4, 2, 3], only elements 2 and 3 are kept in the resulting array. Hence, answer[2] = 2 + 2 + 2 + 3 + 3.
 ```
 
+**Example 2:**
+
+```
+Input: nums = [3,8,7,8,7,5], k = 2, x = 2
+
+Output: [11,15,15,15,12]
+
+Explanation:
+
+Since k == x, answer[i] is equal to the sum of the subarray nums[i..i + k - 1].
+```
 
 ## 结语
 

leetcode/3301-3400/3321.Find-X-Sum-of-All-K-Long-Subarrays-II/Solution.go

@@ -1,5 +1,107 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import (
+	"github.com/emirpasic/gods/v2/trees/redblacktree"
+)
+
+func Solution(nums []int, k int, x int) []int64 {
+	helper := NewHelper(x)
+	ans := []int64{}
+
+	for i := 0; i < len(nums); i++ {
+		helper.Insert(nums[i])
+		if i >= k {
+			helper.Remove(nums[i-k])
+		}
+		if i >= k-1 {
+			ans = append(ans, helper.Get())
+		}
+	}
+
+	return ans
+}
+
+type Helper struct {
+	x      int
+	result int64
+	large  *redblacktree.Tree[pair, struct{}]
+	small  *redblacktree.Tree[pair, struct{}]
+	occ    map[int]int
+}
+
+type pair struct {
+	freq int
+	num  int
+}
+
+func pairComparator(a, b pair) int {
+	if a.freq != b.freq {
+		return a.freq - b.freq
+	}
+	return a.num - b.num
+}
+
+func NewHelper(x int) *Helper {
+	return &Helper{
+		x:      x,
+		result: 0,
+		large:  redblacktree.NewWith[pair, struct{}](pairComparator),
+		small:  redblacktree.NewWith[pair, struct{}](pairComparator),
+		occ:    make(map[int]int),
+	}
+}
+
+func (h *Helper) Insert(num int) {
+	if h.occ[num] > 0 {
+		h.internalRemove(pair{freq: h.occ[num], num: num})
+	}
+	h.occ[num]++
+	h.internalInsert(pair{freq: h.occ[num], num: num})
+}
+
+func (h *Helper) Remove(num int) {
+	h.internalRemove(pair{freq: h.occ[num], num: num})
+	h.occ[num]--
+	if h.occ[num] > 0 {
+		h.internalInsert(pair{freq: h.occ[num], num: num})
+	}
+}
+
+func (h *Helper) Get() int64 {
+	return h.result
+}
+
+func (h *Helper) internalInsert(p pair) {
+	if h.large.Size() < h.x {
+		h.result += int64(p.freq) * int64(p.num)
+		h.large.Put(p, struct{}{})
+	} else {
+		minLarge := h.large.Left().Key
+		if pairComparator(p, minLarge) > 0 {
+			h.result += int64(p.freq) * int64(p.num)
+			h.large.Put(p, struct{}{})
+			toRemove := h.large.Left().Key
+			h.result -= int64(toRemove.freq) * int64(toRemove.num)
+			h.large.Remove(toRemove)
+			h.small.Put(toRemove, struct{}{})
+		} else {
+			h.small.Put(p, struct{}{})
+		}
+	}
+}
+
+func (h *Helper) internalRemove(p pair) {
+	if _, found := h.large.Get(p); found {
+		h.result -= int64(p.freq) * int64(p.num)
+		h.large.Remove(p)
+
+		if h.small.Size() > 0 {
+			maxSmall := h.small.Right().Key
+			h.result += int64(maxSmall.freq) * int64(maxSmall.num)
+			h.small.Remove(maxSmall)
+			h.large.Put(maxSmall, struct{}{})
+		}
+	} else if _, found := h.small.Get(p); found {
+		h.small.Remove(p)
+	}
 }

leetcode/3301-3400/3321.Find-X-Sum-of-All-K-Long-Subarrays-II/Solution_test.go

@@ -10,30 +10,30 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs []int
+		k, x   int
+		expect []int64
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{1, 1, 2, 2, 3, 4, 2, 3}, 6, 2, []int64{6, 10, 12}},
+		{"TestCase2", []int{3, 8, 7, 8, 7, 5}, 2, 2, []int64{11, 15, 15, 15, 12}},
 	}
 
 	//	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.inputs, c.k, c.x)
 			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 %v",
+					c.expect, got, c.inputs, c.k, c.x)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }