DSA · Theory

Breadth First Search Algorithm

Theory

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Breadth First Search Algorithm

If you can teach Breadth First Search Algorithm using find roll 12, you know it. If you only know the heading, you don’t.

Keep Breadth First Search Algorithm small. Meera should finish find roll 12 in a few lines, not a 40-line dump.

Skip Breadth First Search Algorithm and binary search on unsorted data shows up in a sorted list.

Meera ships Breadth First Search Algorithm in a sorted list. That is the use case worth saying.

Don’t do this with Breadth First Search Algorithm: binary search on unsorted data. Interviewers spot it in ten seconds.

Breadth First Search Algorithm is not a lonely heading. Meera ties it to find roll 12.

Viva for Breadth First Search Algorithm — what it is → linear vs binary → the mistake (binary search on unsorted data).

Exam tip

Say Breadth First Search Algorithm in one breath, then linear vs binary, then binary search on unsorted data.

Example

from collections import deque

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

def bfs(start):
    seen, q = {start}, deque([start])
    order = []
    while q:
        u = q.popleft()
        order.append(u)
        for v in graph[u]:
            if v not in seen:
                seen.add(v)
                q.append(v)
    return order

print(bfs(1))

Breadth First Search Algorithm — bFS explores level by level using a queue.

Short notes

DefBreadth First Search Algorithm — Meera uses it for find roll 12 in a sorted list.
RuleBreadth First Search Algorithm → linear vs binary.
RememberBreadth First Search Algorithm + Big-O (a sorted list).
UseBreadth First Search Algorithm in a sorted list (find roll 12).
TrapBreadth First Search Algorithm — binary search on unsorted data.
ExBreadth First Search Algorithm → find roll 12.

from collections import deque graph = {1: [2, 3], 2: [4], 3: [], 4: []} def bfs(start): seen, q = {start}, deque([start]) order = [] while q: u = q.popleft() order.append(u) for v in graph[u]: if v not in seen: seen.add(v) q.append(v) return order print(bfs(1))

Breadth First Search Algorithm

Example

Short notes

Questions

Breadth First Search Algorithm

Example

Short notes

Questions