Apa iku abstract data type (ADT) lan kenapa dipisahake saka implementasine?

Question

Accepted Answer

Sawijining **abstract data type** nemtokake saperangan nilai lan **operasi** sing dibolehake nang kuwi, dijlentrehake kanthi murni dening **perilaku** — dudu dening kode. Implementasi iku struktur nyata (array, linked list, tree) sing ngrealisasi perilaku kuwi.

## ADT sing padha, implementasi beda-beda

```text
ADT "Queue":  enqueue, dequeue, peek  (FIFO contract)

Implementation A: array + two indices (ring buffer)
Implementation B: doubly linked list with head/tail pointers
Both honor the SAME contract; cost profiles differ.
```

## Sebabe dipisahake

```python
# Callers depend on the CONTRACT, not the internals
class Stack:
    def push(self, x): ...
    def pop(self): ...
    def peek(self): ...
# Swap a list for a linked list internally — callers never change.
```

## ADT umum lan implementasi khas

| ADT | Implementasi khas |
|---|---|
| List | dynamic array, linked list |
| Stack | array, linked list |
| Queue | ring buffer, linked list |
| Map | hash table, balanced tree |
| Priority Queue | binary heap |

## Kenapa penting

Programming menyang ADT (sawijining interface) nglakoke kode supaya luwes: bisa ngoptimasi implementasi mengko tanpa nyudeni sing nggawe panggilan.

Iyine uga nyinaune pangolahan nalar — bisa mutusake *perilaku apa* sing dibutuhake rumiyin, banjur milih struktur paling murah sing nyediyakake kuwi.

ADT	Implementasi khas
List	dynamic array, linked list
Stack	array, linked list
Queue	ring buffer, linked list
Map	hash table, balanced tree
Priority Queue	binary heap