seekworser's Library

This documentation is automatically generated by online-judge-tools/verification-helper

---

Project maintained by seekworser Hosted on GitHub Pages — Theme by mattgraham

competitive/python/bfs.py

• View this file on GitHub
• Last update: 1970-01-01 00:00:00+00:00

Code

from collections import deque


def bfs(n, G):
    # return max length path from node n
    # G = [[[n0, d0], [n1, d1]], [[n2, d2], ...], ...]
    dist = [None] * len(G)
    que = deque([n])
    dist[n] = 0
    while que:
        v = que.popleft()
        d = dist[v]
        for w in G[v]:
            if dist[w[0]] is not None:
                continue
            dist[w[0]] = d + w[1]
            que.append(w[0])
    d = max(dist)
    return dist.index(d), d

N = int(input())
G = [[] for _ in range(N)]
for _ in range(N - 1):
    A, B = [int(i) for i in input().split(" ")]
    G[A - 1].append([B - 1, 1])
    G[B - 1].append([A - 1, 1])

u, _ = bfs(0, G)
_, d = bfs(u, G)
print(d + 1)

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.11.3/x64/lib/python3.11/site-packages/onlinejudge_verify/documentation/build.py", line 71, in _render_source_code_stat
    bundled_code = language.bundle(stat.path, basedir=basedir, options={'include_paths': [basedir]}).decode()
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.3/x64/lib/python3.11/site-packages/onlinejudge_verify/languages/python.py", line 96, in bundle
    raise NotImplementedError
NotImplementedError

Back to top page