How does the garbage collector work in Go? Describe the phases and algorithm.

Go uses a trigger-based, concurrent, mark-and-sweep garbage collector with low latency.

Main phases of GC:

1. Mark — the collector traverses all root objects, marking reachable objects.
2. Sweep — unmarked objects are freed.

The algorithm runs concurrently with the program execution, minimizing pauses. Go GC uses a trigger based on the amount of allocated memory and time to initiate garbage collection.

The process roughly looks like this:

• The program allocates memory.
• When a threshold is reached, GC is triggered.
• GC marks objects concurrently with the program.
• After marking, unused objects are cleaned up.

This allows efficient memory management with minimal delays, which is important for server and multithreaded applications.