Dsa Graph Bfs

In this tutorial, you'll learn about How to Fix BFS Graph Errors. We cover key concepts, practical examples, and best practices.

Fix bfs graph errors when queue doesn't track visited or level distances miscalculated.

Quick Fix

Wrong

def bfs(g,s):
    q=[s]
    while q:
        v=q.pop(0); print(v)
        for n in g[v]: q.append(n)

No visited check. Infinite loop on cycles.

Right

from collections import deque
def bfs(g,s):
    q=deque([s]); vis={s}
    while q:
        v=q.popleft(); print(v)
        for n in g[v]:
            if n not in vis: vis.add(n); q.append(n)

Graph {0:[1,2],1:[2],2:[0,3],3:[3]}, BFS from 0 -> 0,1,2,3. O(V+E).

Prevention

Use deque for O(1) popleft. Mark visited when enqueuing, not when processing.

DodaTech Tools

Doda Browser's algorithm visualizer steps through DSA operations line by line. DodaZIP archives implementation patterns for team sharing. Durga Antivirus Pro detects memory corruption patterns in algorithm implementations.

FAQ