Apa iku buffer sirkular (ring buffer) lan kapan sampeyan bakal nggunakaké?

Question

IT Interview Practice · Accepted Answer

**Buffer sirkular** iku array ukuran tetep sing diperlakoni kaya-kaya ujung-ujunge digabung dadi ring. Loro indeks — **head** (maca) lan **tail** (nulis) — maju lan ngubengi nganggo aritmetika modulo, menehi antrian FIFO O(1) tanpa **alokasi** sawise dibuat.

## Cara kerja ngubengi

```text
capacity 5, after writing A,B,C,D and reading A,B:
index:  0   1   2   3   4
      [ . ][ . ][ C ][ D ][ . ]
              head^       tail^   (tail wraps to 0 next write)
```

## Code

```python
class RingBuffer:
    def __init__(self, n):
        self.buf = [None]*n
        self.head = self.tail = self.size = 0
        self.cap = n
    def enqueue(self, x):                  # O(1)
        if self.size == self.cap: raise Exception("full")
        self.buf[self.tail] = x
        self.tail = (self.tail + 1) % self.cap   # wrap
        self.size += 1
    def dequeue(self):                     # O(1)
        x = self.buf[self.head]
        self.head = (self.head + 1) % self.cap    # wrap
        self.size -= 1
        return x
```

| Operasi | Wektu |
|---|---|
| enqueue / dequeue | O(1) |
| spasi | O(n) tetep |

## Kapan nggunakake

- **Buffer streaming / audio / video** — mbatas, throughput tetep.
- **Pipeline produser–konsumen** karo backpressure.
- **Logging N acara paling anyar** (lebokake kang paling lawas).

## Mengapa iku penting

Buffer ring nyediakake prilaku FIFO sing bisa diprediksi lan tanpa alokasi, sing penting ing sistem real-time lan embedded nang pas alokasi dinamis pancet utawa berbahaya.

Ukuran mbatase uga bisa dadi backpressure alami, nyegah produser cepet saka ngasikaté memori.

Cara kerja ngubengi

Code

Kapan nggunakake

Mengapa iku penting

Pitakon sing gegandhengan