Working Hours Register - Industry Coding Framework Level 1

Question

## Problem

Implement a working hours tracking system. Operations are applied in order and each returns a result string.

```
REGISTER employee_id name         -> "registered" or "error" (already exists)
CLOCK_IN employee_id timestamp    -> "clocked_in" or "error" (already clocked in / unknown employee)
CLOCK_OUT employee_id timestamp   -> "clocked_out HH:MM" (duration this session) or "error"
GET_HOURS employee_id             -> total hours worked as "H:MM" or "error"
WHO_IS_IN timestamp               -> comma-separated sorted list of employees clocked in at that time, or "none"
```

Timestamps are Unix seconds. Duration format: hours and minutes (floor to minute).

**Example:**
```
REGISTER e1 Alice     -> "registered"
CLOCK_IN e1 0         -> "clocked_in"
CLOCK_OUT e1 3900     -> "clocked_out 1:05"
GET_HOURS e1          -> "1:05"
CLOCK_IN e1 7200
CLOCK_IN e2 ...       # error: e2 not registered
WHO_IS_IN 7300        -> "Alice"
```

## Follow-ups
- How do you compute `WHO_IS_IN` efficiently if the employee list is large? (interval overlap query)
- Extend to support `GET_HOURS_RANGE employee start end` -- hours worked within a time window.
- How would you handle clock-in without a subsequent clock-out (employee forgot to clock out)?

Working Hours Register - Industry Coding Framework Level 1

Question Details

Full Details

Topics

More from Codesignal