Mutual Translation Routes

PandasMediumMid level~10 min

Problem

DataFrame `route` has columns `src` and `dst`, one row per directed route. A pair is mutual when a distinct row exists for both directions: row (a -> b) and a different row (b -> a). This requires two separate rows, so a self-loop (x -> x) is mutual only when it appears at least twice. Report each mutual pair once, normalized so `src <= dst`.

Return columns `src`, `dst`, sorted by `src` then `dst`.

Input data

Example rows — the live problem includes the full dataset.

route

src	dst
10	20
20	10
30	40
50	50
50	50

Expected output

Your answer should return 2 rows with the columns src, dst.

Starter code (Pandas (Python))

import pandas as pd

def mutual_translation_routes(route) -> pd.DataFrame:
    # Your code here
    return route

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