DSA · Theory

Line Graph

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Theory

258/810

Line Graph

If you can teach Line Graph using bus routes, you know it. If you only know the heading, you don’t.

Keep Line Graph small. Ananya should finish bus routes in a few lines, not a 40-line dump.

Skip Line Graph and no visited set → infinite loop shows up in a city map.

Line Graph shows up in a city map. Name bus routes, not “a real-world scenario”.

Line Graph miss — no visited set → infinite loop. Fix it before you talk about advanced DSA.

Line Graph is not a lonely heading. Ananya ties it to bus routes.

One breath for Line Graph, then bus routes, then no visited set → infinite loop. Sit down.

Exam tip

For Line Graph: definition + a city map + one failure.

Example

# adjacency list
graph = {
    "A": [("B", 2), ("C", 5)],
    "B": [("A", 2), ("C", 1)],
    "C": [("A", 5), ("B", 1)],
}
for u, edges in graph.items():
    print(u, "->", edges)

Line Graph — graphs are often stored as adjacency lists: vertex → list of (neighbor, weight).

Short notes

DefLine Graph — Ananya uses it for bus routes in a city map.
RuleLine Graph → BFS queue / DFS stack.
RememberLine Graph + time vs memory (a city map).
UseLine Graph in a city map (bus routes).
TrapLine Graph — no visited set → infinite loop.
ExLine Graph → bus routes.

DSA · Theory

Line Graph

← All stacks

Theory

258/810

Line Graph

If you can teach Line Graph using bus routes, you know it. If you only know the heading, you don’t.

Keep Line Graph small. Ananya should finish bus routes in a few lines, not a 40-line dump.

Skip Line Graph and no visited set → infinite loop shows up in a city map.

Line Graph shows up in a city map. Name bus routes, not “a real-world scenario”.

Line Graph miss — no visited set → infinite loop. Fix it before you talk about advanced DSA.

Line Graph is not a lonely heading. Ananya ties it to bus routes.

One breath for Line Graph, then bus routes, then no visited set → infinite loop. Sit down.

Exam tip

For Line Graph: definition + a city map + one failure.

Example

# adjacency list
graph = {
    "A": [("B", 2), ("C", 5)],
    "B": [("A", 2), ("C", 1)],
    "C": [("A", 5), ("B", 1)],
}
for u, edges in graph.items():
    print(u, "->", edges)

Line Graph — graphs are often stored as adjacency lists: vertex → list of (neighbor, weight).

Short notes

DefLine Graph — Ananya uses it for bus routes in a city map.
RuleLine Graph → BFS queue / DFS stack.
RememberLine Graph + time vs memory (a city map).
UseLine Graph in a city map (bus routes).
TrapLine Graph — no visited set → infinite loop.
ExLine Graph → bus routes.

Line Graph

Example

Short notes

Questions

Line Graph

Example

Short notes

Questions