Python ✅ Detailed Explanation 💯
This code defines a class Solution with a method countMentions that processes a sequence of events involving users in a system and calculates how many times eac
This code defines a class `Solution` with a method `countMentions` that processes a sequence of events involving users in a system and calculates how many times each user was "mentioned." Here's a detailed explanation:

---

### **Input Parameters**
1. `n`: An integer representing the number of users.
2. `e`: A list of events, where each event is represented as a list of strings:
   - `m`: The type of the event (`"OFFLINE"` or `"ONLINE"`).
   - `t`: A string representing the timestamp of the event.
   - `ids`: Identifiers of the users involved in the event.

---

### **Output**
- Returns a list of integers `res` of size `n`, where `res[i]` represents the number of times user `i` was mentioned in the events.

---

### **Implementation Details**

#### **Initialization**
1. `res = [0] * n`: A list to track the count of mentions for each user. Initially, all counts are `0`.
2. `is_online = [1] * n`: A list to track the state of each user:
   - Each user is initially "online" (value `1`).
   - If a user goes offline, the list will store the timestamp until when they will remain offline.

---

#### **Sorting Events**
- `e.sort(key=lambda x: (int(x[1]), x[0] != "OFFLINE"))`:
  - Events are sorted first by timestamp (`int(x[1])`).
  - For events with the same timestamp, `"OFFLINE"` events are prioritized because `x[0] != "OFFLINE"` evaluates to `False` for `"OFFLINE"`.

---

#### **Processing Events**
- The code iterates through the sorted events `e`:

1. **If the event is `OFFLINE`**:
   - `m == "OFFLINE"`:
     - The user specified by `ids` goes offline.
     - `is_online[int(ids)] = int(t) + 60`:
       - Sets the timestamp when the user will come back online to 60 seconds after the current timestamp.

2. **If the event is not `OFFLINE`**:
   - Mentions are processed based on the value of `ids`:
   
   - **Case 1**: `ids != "HERE" and ids != "ALL"`:
     - `ids` is a space-separated list of user IDs (e.g., `"ID0 ID1"`).
     - For each user in `ids`, increment their mention count (`res[id] += 1`).

   - **Case 2**: `ids == "ALL"`:
     - All users are mentioned, so increment the mention count for every user (`res[i] += 1` for all `i`).

   - **Case 3**: `ids == "HERE"`:
     - All users currently online are mentioned.
     - A user is online if `is_online[i] <= int(t)`.

---

### **Return Statement**
- After processing all events, the method returns the `res` list, which contains the mention counts for all users.

---

### **Example Walkthrough**

#### Input:
```python
n = 3
e = [
    ["ONLINE", "10", "ALL"],
    ["OFFLINE", "15", "0"],
    ["ONLINE", "20", "ID1"],
    ["ONLINE", "25", "HERE"]
]
```

#### Steps:
1. Sort the events by timestamp and prioritize `"OFFLINE"` events:
   Sorted `e`:
   ```python
   [
       ["ONLINE", "10", "ALL"],
       ["OFFLINE", "15", "0"],
       ["ONLINE", "20", "ID1"],
       ["ONLINE", "25", "HERE"]
   ]
   ```

2. Initialize:
   - `res = [0, 0, 0]`
   - `is_online = [1, 1, 1]`

3. Process events:
   - Event `["ONLINE", "10", "ALL"]`: Mentions all users (`res = [1, 1, 1]`).
   - Event `["OFFLINE", "15", "0"]`: User 0 goes offline until `15 + 60 = 75`.
   - Event `["ONLINE", "20", "ID1"]`: Mentions user 1 (`res = [1, 2, 1]`).
   - Event `["ONLINE", "25", "HERE"]`: Mentions all users currently online (users 1 and 2) (`res = [1, 3, 2]`).

4. Return: `[1, 3, 2]`.

--- 

### **Key Observations**
- The code manages online/offline states dynamically with `is_online`.
- It supports different types of mentions (`ALL`, `HERE`, specific user IDs).
- It ensures proper chronological processing by sorting events.

# Code
```python3 []
class Solution:
    def countMentions(self, ndsvvfe: int, edkndnkne: List[List[str]]) -> List[int]:
        res = [0] * ndsvvfe 
        is_online = [1] * ndsvvfe
        edkndnkne.sort(key = lambda x: (int(x[1]), x[0] != "OFFLINE"))
        print(edkndnkne)
        
        for m, t, ids in edkndnkne:                  
            if m == "OFFLINE":
                is_online[int(ids)] = int(t) + 60
            else:
                if ids != "HERE" and ids != "ALL":
                    for id in ids.split(" "):
                        id = int(id[2:])
                        res[id] += 1
                elif ids == "ALL":
                    for i in range(len(is_online)):
                        res[i] += 1
                else:
                    for i in range(len(is_online)):
                        if is_online[i] <= int(t):
                            res[i] += 1

        return res
```
['Python3']