Add solution and test-cases for problem 3433

Author: 0xff-dev

leetcode/3401-3500/3433.Count-Mentions-Per-User/README.md

@@ -1,28 +1,80 @@
 # [3433.Count Mentions Per User][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 `numberOfUsers` representing the total number of users and an array `events` of size `n x 3`.
+
+Each `events[i]` can be either of the following two types:
+
+1. **Message Event**: `["MESSAGE", "timestampi", "mentions_stringi"]`
+
+- This event indicates that a set of users was mentioned in a message at `timestampi`.
+- The `mentions_stringi` string can contain one of the following tokens:
+
+    - `id<number>`: where `<number>` is an integer in range `[0,numberOfUsers - 1]`. There can be **multiple** ids separated by a single whitespace and may contain duplicates. This can mention even the offline users.
+    - `ALL`: mentions **all** users.
+    - `HERE`: mentions all **online** users.
+
+2. **Offline Event**: `["OFFLINE", "timestampi", "idi"]`
+
+    - This event indicates that the user `idi` had become offline at `timestampi` for **60 time units**. The user will automatically be online again at time `timestampi + 60`.
+
+Return an array `mentions` where `mentions[i]` represents the number of mentions the user with id `i` has across all `MESSAGE` events.
+
+All users are initially online, and if a user goes offline or comes back online, their status change is processed before handling any message event that occurs at the same timestamp.
+
+**Note** that a user can be mentioned **multiple** times in a **single** message event, and each mention should be counted **separately**.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: numberOfUsers = 2, events = [["MESSAGE","10","id1 id0"],["OFFLINE","11","0"],["MESSAGE","71","HERE"]]
+
+Output: [2,2]
+
+Explanation:
+
+Initially, all users are online.
+
+At timestamp 10, id1 and id0 are mentioned. mentions = [1,1]
+
+At timestamp 11, id0 goes offline.
+
+At timestamp 71, id0 comes back online and "HERE" is mentioned. mentions = [2,2]
+```
+
+**Example 2:**
+
 ```
+Input: numberOfUsers = 2, events = [["MESSAGE","10","id1 id0"],["OFFLINE","11","0"],["MESSAGE","12","ALL"]]
 
-## 题意
-> ...
+Output: [2,2]
 
-## 题解
+Explanation:
 
-### 思路1
-> ...
-Count Mentions Per User
-```go
+Initially, all users are online.
+
+At timestamp 10, id1 and id0 are mentioned. mentions = [1,1]
+
+At timestamp 11, id0 goes offline.
+
+At timestamp 12, "ALL" is mentioned. This includes offline users, so both id0 and id1 are mentioned. mentions = [2,2]
 ```
 
+**Example 3:**
+
+```
+Input: numberOfUsers = 2, events = [["OFFLINE","10","0"],["MESSAGE","12","HERE"]]
+
+Output: [0,1]
+
+Explanation:
+
+Initially, all users are online.
+
+At timestamp 10, id0 goes offline.
+
+At timestamp 12, "HERE" is mentioned. Because id0 is still offline, they will not be mentioned. mentions = [0,1]
+```
 
 ## 结语
 

leetcode/3401-3500/3433.Count-Mentions-Per-User/Solution.go

@@ -1,5 +1,82 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import (
+	"sort"
+	"strconv"
+	"strings"
+)
+
+type Event struct {
+	Type      string
+	Timestamp int
+	All, Here bool
+	Users     []int
+}
+
+func Solution(numberOfUsers int, events [][]string) []int {
+	cEvents := make([]Event, 0)
+	var uid int
+	for i := range events {
+		t, _ := strconv.Atoi(events[i][1])
+		e := Event{
+			Type:      events[i][0],
+			Timestamp: t,
+		}
+		if e.Type == "OFFLINE" {
+			uid, _ = strconv.Atoi(events[i][2])
+			e.Users = append(e.Users, uid)
+			cEvents = append(cEvents, e)
+			continue
+		}
+
+		if events[i][2] == "ALL" {
+			e.All = true
+		} else if events[i][2] == "HERE" {
+			e.Here = true
+		} else {
+			users := strings.Split(events[i][2], " ")
+			e.Users = make([]int, len(users))
+			for i, u := range users {
+				uid, _ = strconv.Atoi(u[2:])
+				e.Users[i] = uid
+			}
+		}
+
+		cEvents = append(cEvents, e)
+	}
+	sort.Slice(cEvents, func(i, j int) bool {
+		a, b := cEvents[i], cEvents[j]
+		if a.Timestamp == b.Timestamp {
+			return a.Type == "OFFLINE"
+		}
+		return a.Timestamp < b.Timestamp
+	})
+	onlineTime := make([]int, numberOfUsers)
+	ret := make([]int, numberOfUsers)
+
+	for _, e := range cEvents {
+		if e.Type == "MESSAGE" {
+			if e.All {
+				for i := range ret {
+					ret[i]++
+				}
+			} else if e.Here {
+				for i := range ret {
+					if e.Timestamp < onlineTime[i] {
+						continue
+					}
+					ret[i]++
+				}
+			} else {
+				for _, u := range e.Users {
+					ret[u]++
+				}
+			}
+			continue
+		}
+
+		onlineTime[e.Users[0]] = e.Timestamp + 60
+	}
+
+	return ret
 }

leetcode/3401-3500/3433.Count-Mentions-Per-User/Solution_test.go

@@ -10,30 +10,31 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs int
+		events [][]string
+		expect []int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", 2, [][]string{{"MESSAGE", "10", "id1 id0"}, {"OFFLINE", "11", "0"}, {"MESSAGE", "71", "HERE"}}, []int{2, 2}},
+		{"TestCase2", 2, [][]string{{"MESSAGE", "10", "id1 id0"}, {"OFFLINE", "11", "0"}, {"MESSAGE", "12", "ALL"}}, []int{2, 2}},
+		{"TestCase3", 2, [][]string{{"OFFLINE", "10", "0"}, {"MESSAGE", "12", "HERE"}}, []int{0, 1}},
 	}
 
 	//	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.events)
 			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.inputs, c.events)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }