Activity Selection (Interval Scheduling) in Java: Explanation & Practice

Select maximum non-overlapping activities

Problem summary

Given n activities with start and end times, select the maximum number of activities that can be performed by a single person (no overlapping).

Starter code

public class Main {
    public static void main(String[] args) {
        int[] start = {1, 3, 0, 5, 8, 5};
        int[] end = {2, 4, 6, 7, 9, 9};
        
        // Greedy: always pick activity that ends earliest
        // Sort by end time
        // Select if start >= last selected end
        // Print: Max activities: 4
    }
}

Expected output and test cases

Select 4 non-overlapping
```
Max activities: 4
```
Only 2 possible
```
Max activities: 2
```
All overlap → pick 1
```
Max activities: 1
```

Hints

Sort activities by end time
Always pick the activity that finishes earliest
This leaves maximum room for remaining activities
After picking, skip all overlapping activities

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