DSA · Theory

Stack Organisation

Theory

492/810

Stack Organisation is simple if you keep it on paper. Meera uses it for undo typing in a tiny editor.

Keep Stack Organisation small. Meera should finish undo typing in a few lines, not a 40-line dump.

Stack Organisation exists so Meera can keep undo typing correct in a tiny editor.

Meera ships Stack Organisation in a tiny editor. That is the use case worth saying.

Don’t do this with Stack Organisation — pop on empty. Interviewers spot it in ten seconds.

Place Stack Organisation next to nearby DSA work — push / pop LIFO is the link.

Close Stack Organisation with — “If I skip it, undo typing goes wrong like this: pop on empty.”

Diagram

    | 3 |  ← top (pop)
    | 2 |
    | 1 |
    LIFO

Exam tip

For Stack Organisation: definition + a tiny editor + one failure.

stack = []
stack.append(10)   # push
stack.append(20)
print(stack.pop()) # 20
print(stack[-1])   # peek → 10

Stack Organisation — stack is LIFO: push/pop from the same end.