DSA · Theory

Topological Sorting

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Theory

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Topological Sorting

If you can teach Topological Sorting using names A→Z, you know it. If you only know the heading, you don’t.

For Topological Sorting, a dry-run table is in play. Don’t blame it until you have traced names A→Z.

Skip Topological Sorting and unstable sort when equal keys matter shows up in the roll list.

Use Topological Sorting when names A→Z must stay clear. If a simpler DSA step works, use that instead.

If names A→Z breaks under Topological Sorting, check unstable sort when equal keys matter first.

Place Topological Sorting next to nearby DSA work — n log n vs n² is the link.

Close Topological Sorting with — “If I skip it, names A→Z goes wrong like this: unstable sort when equal keys matter.”

Exam tip

Board: names A→Z. Dry-run Topological Sorting. Name the trap: unstable sort when equal keys matter.

Example

# Topological Sorting
data = [4, 1, 3]
print("start", data)
if data[0] > data[1]:
    data[0], data[1] = data[1], data[0]
print("after one step", data)

Topological Sorting: dry-run [4, 1, 3]. Say the list after one step.

Short notes

DefTopological Sorting — Amit uses it for names A→Z in the roll list.
RuleTopological Sorting → n log n vs n².
RememberTopological Sorting + a dry-run table (the roll list).
UseTopological Sorting in the roll list (names A→Z).
TrapTopological Sorting — unstable sort when equal keys matter.
ExTopological Sorting → names A→Z.

DSA · Theory

Topological Sorting

← All stacks

Theory

188/810

Topological Sorting

If you can teach Topological Sorting using names A→Z, you know it. If you only know the heading, you don’t.

For Topological Sorting, a dry-run table is in play. Don’t blame it until you have traced names A→Z.

Skip Topological Sorting and unstable sort when equal keys matter shows up in the roll list.

Use Topological Sorting when names A→Z must stay clear. If a simpler DSA step works, use that instead.

If names A→Z breaks under Topological Sorting, check unstable sort when equal keys matter first.

Place Topological Sorting next to nearby DSA work — n log n vs n² is the link.

Close Topological Sorting with — “If I skip it, names A→Z goes wrong like this: unstable sort when equal keys matter.”

Exam tip

Board: names A→Z. Dry-run Topological Sorting. Name the trap: unstable sort when equal keys matter.

Example

# Topological Sorting
data = [4, 1, 3]
print("start", data)
if data[0] > data[1]:
    data[0], data[1] = data[1], data[0]
print("after one step", data)

Topological Sorting: dry-run [4, 1, 3]. Say the list after one step.

Short notes

DefTopological Sorting — Amit uses it for names A→Z in the roll list.
RuleTopological Sorting → n log n vs n².
RememberTopological Sorting + a dry-run table (the roll list).
UseTopological Sorting in the roll list (names A→Z).
TrapTopological Sorting — unstable sort when equal keys matter.
ExTopological Sorting → names A→Z.

Topological Sorting

Example

Short notes

Questions

Topological Sorting

Example

Short notes

Questions