Is Invalid Tweets II easy or hard?

Invalid Tweets II is categorized as an Easy database problem. The challenge mainly checks familiarity with SQL string functions and the common trick of counting characters using a LENGTH difference.

Invalid Tweets II Python/Java solution

In Python, compute len(content) - len(content.replace('@','')). If the result is greater than three, the tweet is invalid. The same logic works in Java using string length and replace methods, making the solution consistent across languages.

How to solve Invalid Tweets II in O(n)?

Within database queries, the closest practical complexity is O(n * m) because each tweet string must be scanned. Using LENGTH(content) - LENGTH(REPLACE(content, '@', '')) counts mentions in a single pass per string and avoids extra joins or loops, which keeps the query efficient.

What is the best approach for Invalid Tweets II?

The most efficient solution counts the number of '@' characters using LENGTH() and REPLACE() functions. Compute LENGTH(content) minus LENGTH(REPLACE(content, '@', '')). If the result is greater than three, the tweet is invalid. This approach runs in O(n * m) time where n is the number of tweets and m is the average tweet length.

Is Invalid Tweets II asked at Google/Amazon/Meta?

Problems like Invalid Tweets II appear in SQL interview rounds at companies that test database fundamentals. The question focuses on string manipulation and filtering rows using SQL functions, which are common skills evaluated in data engineering and backend interviews.

What data structure is used in Invalid Tweets II?

No specialized data structure is required. The solution operates directly on strings stored in a database column and uses SQL string functions such as LENGTH() and REPLACE() to compute the number of occurrences of a character.

What is the time complexity of Invalid Tweets II?

The solution scans each tweet string to compute its length and the length after replacement. If n is the number of rows and m is the average length of each tweet, the complexity is O(n * m). Space complexity remains O(1) because no additional structures are created.

3150. Invalid Tweets II - Practice Online

3150. Invalid Tweets II

Easy87.0% AcceptancePremium

PremiumFree on FleetCode

Table: Tweets

+----------------+---------+
| Column Name    | Type    |
+----------------+---------+
| tweet_id       | int     |
| content        | varchar |
+----------------+---------+
tweet_id is the primary key (column with unique values) for this table.
This table contains all the tweets in a social media app.

Write a solution to find invalid tweets. A tweet is considered invalid if it meets any of the following criteria:

It exceeds 140 characters in length.
It has more than 3 mentions.
It includes more than 3 hashtags.

Return the result table ordered by tweet_id in ascending order.

The result format is in the following example.

Example:

Input:

Tweets table:

  +----------+-----------------------------------------------------------------------------------+
  | tweet_id | content                                                                           |
  +----------+-----------------------------------------------------------------------------------+
  | 1        | Traveling, exploring, and living my best life @JaneSmith @SaraJohnson @LisaTaylor |
  |          | @MikeBrown #Foodie #Fitness #Learning                                             | 
  | 2        | Just had the best dinner with friends! #Foodie #Friends #Fun                      |
  | 4        | Working hard on my new project #Work #Goals #Productivity #Fun                    |
  +----------+-----------------------------------------------------------------------------------+

Output:

  +----------+
  | tweet_id |
  +----------+
  | 1        |
  | 4        |
  +----------+

Explanation:

tweet_id 1 contains 4 mentions.
tweet_id 4 contains 4 hashtags.

Output table is ordered by tweet_id in ascending order.

{"headers": {"Tweets": ["tweet_id", "content"]}, "rows": {"Tweets": [[1, "What an amazing meal @MaxPower @AlexJones @JohnDoe #Learning #Fitness #Love"], [2, "Learning something new every day @AnnaWilson #Learning #Foodie"], [3, "Never been happier about today's achievements @SaraJohnson @JohnDoe @AnnaWilson #Fashion"], [4, "Traveling, exploring, and living my best life @JaneSmith @JohnDoe @ChrisAnderson @AlexJones #WorkLife #Travel"], [5, "Work hard, play hard, and cherish every moment @AlexJones #Fashion #Foodie"], [6, "Never been happier about today's achievements @ChrisAnderson #Fashion #WorkLife"], [7, "So grateful for today's experiences @AnnaWilson @LisaTaylor @ChrisAnderson @MikeBrown #Fashion #HappyDay #WorkLife #Nature"], [8, "What an amazing meal @EmilyClark @AlexJones @MikeBrown #Fitness"], [9, "Learning something new every day @EmilyClark @AnnaWilson @MaxPower #Travel"], [10, "So grateful for today's experiences @ChrisAnderson #Nature"], [11, "So grateful for today's experiences @AlexJones #Art #WorkLife"], [12, "Learning something new every day @JaneSmith @MikeBrown #Travel"], [13, "What an amazing meal @EmilyClark @JohnDoe @LisaTaylor @MaxPower #Foodie #Fitness"], [14, "Work hard, play hard, and cherish every moment @LisaTaylor @SaraJohnson @MaxPower @ChrisAnderson #TechLife #Nature #Music"], [15, "What a beautiful day it is @EmilyClark @MaxPower @SaraJohnson #Fashion"], [16, "What a beautiful day it is @AnnaWilson @JaneSmith #Fashion #Love #TechLife"]]}}