Buggy python submission (verdict: Runtime Error):
def dfs(u, prev, visited, lowest, parent, prenum):
    # ????????? u ????¨????????????´????????????
    visited |= {u}
    prenum[u] = len(visited)
    lowest[u] = len(visited)

    for v in g[u]:
        if v not in  visited:
            # ????????? u ??????????????? v ????¨????????????´????????????
            parent[v] = u
            dfs(v, u, visited, lowest, parent, prenum)
            # ????????? v ?????¢?´¢?????????????????´????????????
            lowest[u] = min(lowest[u], lowest[v])
        elif v != prev:
            # ??¨?????? u --> v ??? Back-edge ?????´????????????
            lowest[u] = min(lowest[u], prenum[v])
    # ????????? u ?????¢?´¢?????????????????´????????????

from sys import stdin
readline = stdin.readline


v, e = map(int, readline().split())
from collections import defaultdict
g = defaultdict(list)

for _ in range(e):
    s, t = map(int, readline().split())
    g[s].append(t)
    g[t].append(s)
    
visited = set()
lowest = [None] * v
parent = [None] * v
prenum = [None] * v
root = 0
# lowest ????¨????
dfs(root, -1, visited, lowest, parent, prenum)

child = defaultdict(list)
for i in range(v):
    if parent[i] is not None:
        child[parent[i]].append(i)
if 2 <= len(child[root]):
    print(root)
for i in range(1, v):
    if child[i] and any(prenum[i] <= lowest[j] for j in child[i]):
        print(i)

Fixed submission:
from sys import stdin
readline = stdin.readline


def main():
    v, e = map(int, readline().split())
    from collections import defaultdict
    g = defaultdict(list)

    for _ in range(e):
        s, t = map(int, readline().split())
        g[s].append(t)
        g[t].append(s)

    visited = set()
    lowest = [None] * v
    parent = [None] * v
    prenum = [None] * v
    child = defaultdict(list)
    root = 0

    # dfs??§tree?????????
    stack = [(root, None)]
    while stack:
        u, prev = stack.pop()
        if u not in visited:
            parent[u] = prev
            if prev is not None:
                child[prev].append(u)
            visited |= {u}
            prenum[u] = lowest[u] = len(visited)

        stack.extend([(v, u) for v in g[u] if v not in visited])

    # lowest????¨????
    from collections import Counter
    leaf = [i for i in range(v) if not child[i]]
    unfinished = Counter()
    for li in leaf:
        while li is not None:
            candidate = [prenum[li]] + [prenum[i] for i in g[li] if i != parent[li]] + [lowest[i] for i in child[li]]
            lowest[li] = min(candidate)
            li = parent[li]
            if li is not None and 1 < len(child[li]):
                unfinished[li] += 1
                if unfinished[li] < len(child[li]):
                    break

    # ??£???????????????
    if 2 <= len(child[root]):
        print(root)
    for i in range(1, v):
        if child[i] and any(prenum[i] <= lowest[j] for j in child[i]):
            print(i)
main()

Buggy python submission (verdict: Runtime Error):
from sys import stdin
readline = stdin.readline

v, e = map(int, readline().split())
from collections import defaultdict
g = defaultdict(list)

for _ in range(e):
    s, t = map(int, readline().split())
    g[s].append(t)
    g[t].append(s)
    
visited = set()
lowest = [None] * v
parent = [None] * v
prenum = [None] * v
child = defaultdict(list)
root = 0

# dfs??§tree?????????
que = deque([root])
while que:
    u = que.popleft()
    visited |= {u}
    prenum[u] = lowest[u] = len(visited)
    for vi in g[u]:
        if vi not in visited:
            parent[vi] = u
            que.append(vi)

for i in range(v):
    if parent[i] is not None:
        child[parent[i]].append(i)
            
leaf = [i for i in range(v) if not child[i]]
for li in leaf:
    while li is not None:
        candidate = [prenum[li]] + [prenum[i] for i in g[li] if i != parent[li]] + [lowest[i] for i in child[i]]
        lowest[li] = min(candidate)
        li = parent[li]

        
if 2 <= len(child[root]):
    print(root)
for i in range(1, v):
    if child[i] and any(prenum[i] <= lowest[j] for j in child[i]):
        print(i)

Fixed submission:
from sys import stdin
readline = stdin.readline


def main():
    v, e = map(int, readline().split())
    from collections import defaultdict
    g = defaultdict(list)

    for _ in range(e):
        s, t = map(int, readline().split())
        g[s].append(t)
        g[t].append(s)

    visited = set()
    lowest = [None] * v
    parent = [None] * v
    prenum = [None] * v
    child = defaultdict(list)
    root = 0

    # dfs??§tree?????????
    stack = [(root, None)]
    while stack:
        u, prev = stack.pop()
        if u not in visited:
            parent[u] = prev
            if prev is not None:
                child[prev].append(u)
            visited |= {u}
            prenum[u] = lowest[u] = len(visited)

        stack.extend([(v, u) for v in g[u] if v not in visited])

    # lowest????¨????
    from collections import Counter
    leaf = [i for i in range(v) if not child[i]]
    unfinished = Counter()
    for li in leaf:
        while li is not None:
            candidate = [prenum[li]] + [prenum[i] for i in g[li] if i != parent[li]] + [lowest[i] for i in child[li]]
            lowest[li] = min(candidate)
            li = parent[li]
            if li is not None and 1 < len(child[li]):
                unfinished[li] += 1
                if unfinished[li] < len(child[li]):
                    break

    # ??£???????????????
    if 2 <= len(child[root]):
        print(root)
    for i in range(1, v):
        if child[i] and any(prenum[i] <= lowest[j] for j in child[i]):
            print(i)
main()

Buggy python submission (verdict: Runtime Error):
from sys import stdin
readline = stdin.readline

v, e = map(int, readline().split())
from collections import defaultdict
g = defaultdict(list)

for _ in range(e):
    s, t = map(int, readline().split())
    g[s].append(t)
    g[t].append(s)
    
visited = set()
lowest = [None] * v
parent = [None] * v
prenum = [None] * v
child = defaultdict(list)
root = 0

# dfs??§tree?????????
stack = [(root, None)]
while stack:
    u, prev = stack.pop()
    if u not in visited:
        parent[u] = prev
        if prev is not None:
            child[prev].append(u)
    visited |= {u}
    prenum[u] = lowest[u] = len(visited)
    
    stack.extend([(v, u) for v in g[u] if v not in visited])
            
leaf = [i for i in range(v) if not child[i]]
for li in leaf:
    while li is not None:
        candidate = [prenum[li]] + [prenum[i] for i in g[li] if i != parent[li]] + [lowest[i] for i in child[i]]
        lowest[li] = min(candidate)
        li = parent[li]

if 2 <= len(child[root]):
    print(root)
for i in range(1, v):
    if child[i] and any(prenum[i] <= lowest[j] for j in child[i]):
        print(i)

Fixed submission:
from sys import stdin
readline = stdin.readline


def main():
    v, e = map(int, readline().split())
    from collections import defaultdict
    g = defaultdict(list)

    for _ in range(e):
        s, t = map(int, readline().split())
        g[s].append(t)
        g[t].append(s)

    visited = set()
    lowest = [None] * v
    parent = [None] * v
    prenum = [None] * v
    child = defaultdict(list)
    root = 0

    # dfs??§tree?????????
    stack = [(root, None)]
    while stack:
        u, prev = stack.pop()
        if u not in visited:
            parent[u] = prev
            if prev is not None:
                child[prev].append(u)
            visited |= {u}
            prenum[u] = lowest[u] = len(visited)

        stack.extend([(v, u) for v in g[u] if v not in visited])

    # lowest????¨????
    from collections import Counter
    leaf = [i for i in range(v) if not child[i]]
    unfinished = Counter()
    for li in leaf:
        while li is not None:
            candidate = [prenum[li]] + [prenum[i] for i in g[li] if i != parent[li]] + [lowest[i] for i in child[li]]
            lowest[li] = min(candidate)
            li = parent[li]
            if li is not None and 1 < len(child[li]):
                unfinished[li] += 1
                if unfinished[li] < len(child[li]):
                    break

    # ??£???????????????
    if 2 <= len(child[root]):
        print(root)
    for i in range(1, v):
        if child[i] and any(prenum[i] <= lowest[j] for j in child[i]):
            print(i)
main()

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin
from collections import deque
readline = stdin.readline

v, e = map(int, readline().split())
from collections import defaultdict
g = defaultdict(list)

for _ in range(e):
    s, t = map(int, readline().split())
    g[s].append(t)
    g[t].append(s)
    
visited = set()
lowest = [None] * v
parent = [None] * v
prenum = [None] * v
child = defaultdict(list)
root = 0

# dfs??§tree?????????
stack = [(root, None)]
while stack:
    u, prev = stack.pop()
    if u not in visited:
        parent[u] = prev
        if prev is not None:
            child[prev].append(u)
        visited |= {u}
        prenum[u] = lowest[u] = len(visited)
    
    stack.extend([(v, u) for v in g[u] if v not in visited])
            
leaf = [i for i in range(v) if not child[i]]
for li in leaf:
    while li is not None:
        candidate = [prenum[li]] + [prenum[i] for i in g[li] if i != parent[li]] + [lowest[i] for i in child[li]]
        lowest[li] = min(candidate)
        li = parent[li]

if 2 <= len(child[root]):
    print(root)
for i in range(1, v):
    if child[i] and any(prenum[i] <= lowest[j] for j in child[i]):
        print(i)

Fixed submission:
from sys import stdin
readline = stdin.readline


def main():
    v, e = map(int, readline().split())
    from collections import defaultdict
    g = defaultdict(list)

    for _ in range(e):
        s, t = map(int, readline().split())
        g[s].append(t)
        g[t].append(s)

    visited = set()
    lowest = [None] * v
    parent = [None] * v
    prenum = [None] * v
    child = defaultdict(list)
    root = 0

    # dfs??§tree?????????
    stack = [(root, None)]
    while stack:
        u, prev = stack.pop()
        if u not in visited:
            parent[u] = prev
            if prev is not None:
                child[prev].append(u)
            visited |= {u}
            prenum[u] = lowest[u] = len(visited)

        stack.extend([(v, u) for v in g[u] if v not in visited])

    # lowest????¨????
    from collections import Counter
    leaf = [i for i in range(v) if not child[i]]
    unfinished = Counter()
    for li in leaf:
        while li is not None:
            candidate = [prenum[li]] + [prenum[i] for i in g[li] if i != parent[li]] + [lowest[i] for i in child[li]]
            lowest[li] = min(candidate)
            li = parent[li]
            if li is not None and 1 < len(child[li]):
                unfinished[li] += 1
                if unfinished[li] < len(child[li]):
                    break

    # ??£???????????????
    if 2 <= len(child[root]):
        print(root)
    for i in range(1, v):
        if child[i] and any(prenum[i] <= lowest[j] for j in child[i]):
            print(i)
main()