DSA · Theory

DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List

Theory

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DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List

DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List is a DSA topic. In plain words you use it for folder on disk in a file explorer. Don’t start with a slogan — start with that picture.

Smallest example: left < root < right. Type it, run it, and say what you see. If you can do that from memory, you know DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List.

From the example next to this theory: DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List — dFS goes deep along a path before backtracking — natural with recursion/stack.

Trap — unbalanced BST becoming a list. Fix that before you talk about advanced DSA.

Viva: what is DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List? Then show left < root < right. Then name the trap.

Exam tip

What is DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List? Show this: left < root < right. Trap: unbalanced BST becoming a list.

Example

graph = {1: [2, 3], 2: [4], 3: [], 4: []}

def dfs(u, seen=None):
    if seen is None:
        seen = set()
    seen.add(u)
    order = [u]
    for v in graph[u]:
        if v not in seen:
            order += dfs(v, seen)
    return order

print(dfs(1))

DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List — dFS goes deep along a path before backtracking — natural with recursion/stack.

Short notes

DefDFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List — folder on disk in a file explorer.
Ruleleft < root < right
Trapunbalanced BST becoming a list
Usea file explorer

graph = {1: [2, 3], 2: [4], 3: [], 4: []} def dfs(u, seen=None): if seen is None: seen = set() seen.add(u) order = [u] for v in graph[u]: if v not in seen: order += dfs(v, seen) return order print(dfs(1))

DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List

Example

Short notes

Questions

DFS for an n-ary Tree(Acyclic Graph) Represented as an Adjacency List

Example

Short notes

Questions