Explanation of Overlapping Booking Logic in MyCalendar

• (LC 729)

This document explains the logic used in the following code snippet from the MyCalendar class:

if (start < date.get(1) && end > date.get(0)) {
    return false;  // There's an overlap
}

Purpose

The purpose of this logic is to check whether a new booking overlaps with an existing booking in the calendar. If the new booking overlaps with an existing booking, the function will return false, indicating that the booking cannot be made.

Visual Explanation

Imagine a timeline where each event has a start and an end time. The new event is represented by start and end, while an existing event is represented by date.get(0) (start) and date.get(1) (end).

Cases:

1. No Overlap - New Event is Completely Before the Existing Event

New:      |-----|   
Existing:          |-----|

• Condition: end <= date.get(0)
• Explanation: The new event ends before the existing event starts, so no overlap.

2. No Overlap - New Event is Completely After the Existing Event

New:              |-----|
Existing:  |-----|

• Condition: start >= date.get(1)
• Explanation: The new event starts after the existing event ends, so no overlap.

3. Overlap - New Event Partially Overlaps with the Existing Event

New:       |-------|
Existing:     |------|

• Condition: start < date.get(1) and end > date.get(0)
• Explanation: The new event starts before the existing event ends and ends after the existing event starts, causing a partial overlap.

4. Complete Overlap - New Event Starts and Ends Inside the Existing Event

New:         |---|
Existing:   |-------|

• Condition: start < date.get(1) and end > date.get(0)
• Explanation: Both conditions are true, meaning the new event is entirely within the bounds of the existing event.

5. New Event Engulfs the Existing Event (Starts Before and Ends After)

New:     |-----------|
Existing:   |-----|

• Condition: start < date.get(1) and end > date.get(0)
• Explanation: The new event starts before and ends after the existing event, completely overlapping it.

Breakdown of the Condition:

• start < date.get(1): This checks if the new event starts before the existing event ends.
• end > date.get(0): This checks if the new event ends after the existing event starts.

If both conditions are true, there is an overlap, and the function returns false to indicate that the booking cannot be made.