Lead Climber on Each Route

Problem

DataFrame: `route_assignment` (`route_assignment.csv`)

```text
+------------+------+
| Column | Type |
+------------+------+
| route_id | int |
| climber_id | int |
+------------+------+
Each row assigns one climber to one route. (route_id, climber_id) is unique.
```

DataFrame: `climber` (`climber.csv`)

```text
+------------+--------+
| Column | Type |
+------------+--------+
| climber_id | int |
| handle | object |
| ascents | int |
+------------+--------+
climber_id uniquely identifies each climber.
```

For each route, find the **lead climber(s)**: the assigned climber(s) with the highest `ascents` on that route. Return columns `route_id` and `climber_id`. If two or more climbers on a route tie for the most ascents, return each of them.

Return the rows in any order.

**Example**

Input — `route_assignment`:

```text
route_id climber_id
1 1
1 2
1 3
2 1
2 4
```

Input — `climber`:

```text
climber_id handle ascents
1 Vega 30
2 Ridge 20
3 Crux 30
4 Pitch 20
```

Output:

```text
route_id climber_id
1 1
1 3
2 1
```

On route 1, climbers 1 and 3 both have 30 ascents (the max), so both lead; on route 2, climber 1 (30) beats climber 4 (20).

Input data

Example rows — the live problem includes the full dataset.

Expected output

Your answer should return 3 rows with the columns route_id, climber_id.

Starter code (Pandas (Python))

import pandas as pd

def lead_climber(route_assignment: pd.DataFrame, climber: pd.DataFrame) -> pd.DataFrame:
    # Your code here
    return route_assignment

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