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Description

Editorial

Active Profile Follower Connectivity Report

MEDIUM20 pts

Your analytics team stores social follows in a table named follow.

Columns:

followee: account being followed
follower: account that follows followee

Data guarantees:

(followee, follower) is unique
no account follows itself

Define a two-sided active account as an account that:

follows at least one other account (appears in follower), and
is followed by at least one account (appears in followee).

Task: Return every two-sided active account and how many distinct followers it has.

Output requirements:

Return exactly two columns: follower, num
follower: qualifying account id
num: count of distinct accounts that follow that follower account
Order by follower in ascending alphabetical order

Supported submission environments:

SQL (SQLite 3.27.2)
Pandas (Python)

Example

Input

follow:
| followee | follower |
|----------|----------|
| Alice    | Bob      |
| Bob      | Cena     |
| Bob      | Donald   |
| Donald   | Edward   |

Output

[
  {"follower":"Bob","num":2},
  {"follower":"Donald","num":1}
]

Explanation

Bob and Donald each follow someone and each have incoming followers. Alice is followed but does not follow anyone, so Alice is excluded.

Example

Input

follow:
| followee | follower |
|----------|----------|
| Root     | Leaf1    |
| Root     | Leaf2    |
| Root     | Leaf3    |
| Root     | Leaf4    |

Output

[]

Explanation

Root has inbound followers but no outbound follow. Each Leaf has outbound follow but no inbound followers. No account is active on both sides.

Example

Input

follow:
| followee | follower |
|----------|----------|
| Nina     | Omar     |
| Omar     | Pia      |
| Pia      | Nina     |
| Nina     | Quinn    |
| Ravi     | Nina     |
| Pia      | Ravi     |

Output

[
  {"follower":"Nina","num":2},
  {"follower":"Omar","num":1},
  {"follower":"Pia","num":2},
  {"follower":"Ravi","num":1}
]

Explanation

Nina, Omar, Pia, and Ravi all have at least one incoming and one outgoing follow relation.

Accepted0/0·0% Acceptance

Constraints

0 <= number of rows in follow <= 200,000
1 <= length of each account identifier <= 64
(followee, follower) is unique
followee != follower for every row
Use SQLite 3.27.2 semantics for SQL submissions
For Pandas submissions, return a DataFrame with columns: follower, num
num must represent distinct inbound follower count
Output must be ordered by follower ascending

Code

Visualizer

Solutions

14px

Test Cases3

Results

Submissions

follow =

[{"followee":"Donald","follower":"Edward"},{"followee":"Bob","follower":"Cena"},{"followee":"Bob","follower":"Donald"},{"followee":"Alice","follower":"Bob"}]

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101

00:00:00

Description

Editorial

Active Profile Follower Connectivity Report

MEDIUM20 pts

Your analytics team stores social follows in a table named follow.

Columns:

followee: account being followed
follower: account that follows followee

Data guarantees:

(followee, follower) is unique
no account follows itself

Define a two-sided active account as an account that:

follows at least one other account (appears in follower), and
is followed by at least one account (appears in followee).

Task: Return every two-sided active account and how many distinct followers it has.

Output requirements:

Return exactly two columns: follower, num
follower: qualifying account id
num: count of distinct accounts that follow that follower account
Order by follower in ascending alphabetical order

Supported submission environments:

SQL (SQLite 3.27.2)
Pandas (Python)

Example

Input

follow:
| followee | follower |
|----------|----------|
| Alice    | Bob      |
| Bob      | Cena     |
| Bob      | Donald   |
| Donald   | Edward   |

Output

[
  {"follower":"Bob","num":2},
  {"follower":"Donald","num":1}
]

Explanation

Bob and Donald each follow someone and each have incoming followers. Alice is followed but does not follow anyone, so Alice is excluded.

Example

Input

follow:
| followee | follower |
|----------|----------|
| Root     | Leaf1    |
| Root     | Leaf2    |
| Root     | Leaf3    |
| Root     | Leaf4    |

Output

[]

Explanation

Root has inbound followers but no outbound follow. Each Leaf has outbound follow but no inbound followers. No account is active on both sides.

Example

Input

follow:
| followee | follower |
|----------|----------|
| Nina     | Omar     |
| Omar     | Pia      |
| Pia      | Nina     |
| Nina     | Quinn    |
| Ravi     | Nina     |
| Pia      | Ravi     |

Output

[
  {"follower":"Nina","num":2},
  {"follower":"Omar","num":1},
  {"follower":"Pia","num":2},
  {"follower":"Ravi","num":1}
]

Explanation

Nina, Omar, Pia, and Ravi all have at least one incoming and one outgoing follow relation.

Accepted0/0·0% Acceptance

Constraints

0 <= number of rows in follow <= 200,000
1 <= length of each account identifier <= 64
(followee, follower) is unique
followee != follower for every row
Use SQLite 3.27.2 semantics for SQL submissions
For Pandas submissions, return a DataFrame with columns: follower, num
num must represent distinct inbound follower count
Output must be ordered by follower ascending

Code

Visualizer

Solutions

14px

Test Cases3

Results

Submissions

follow =

[{"followee":"Donald","follower":"Edward"},{"followee":"Bob","follower":"Cena"},{"followee":"Bob","follower":"Donald"},{"followee":"Alice","follower":"Bob"}]

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