Problem: 2063C - Remove Exactly Two
Language: PyPy 3-64

Previous submission (verdict: Wrong answer on test 2):
import io
import os
import sys


inf = 10 ** 18
mod = 10 ** 9 + 7

ONLINE_JUDGE = __debug__

if ONLINE_JUDGE:
    R = io.BytesIO(os.read(0, os.fstat(0).st_size)).readline


    def _input() -> str:
        return R().decode()
else:
    R = sys.stdin.readline


    def _input() -> str:
        return R()


def get_int() -> int:
    return int(_input())


def get_str() -> str:
    return _input().strip()


def get_int_list() -> list[int]:
    return list(map(int, _input().strip().split()))


def init_matrix(n_, m_, value_=0) -> list[list]:
    return [[value_] * m_ for _ in range(n_)]


def solve() -> None:
    n = get_int()

    g = init_matrix(n, 0)
    cnt = [0] * n
    pairs = set()
    for i in range(n - 1):
        u, v = get_int_list()
        u -= 1
        v -= 1
        g[v].append(u)
        g[u].append(v)
        cnt[u] += 1
        cnt[v] += 1
        pairs.add((u, v))
        pairs.add((v, u))

    order = sorted(
        range(len(cnt)),
        key=lambda x: cnt[x],
        reverse=True,
    )
    u, v = order[:2]
    h = []
    for i in range(n):
        if cnt[i] == cnt[v]:
            h.append(i)

    if cnt[u] != cnt[v]:
        for w in h:
            if (u, w) not in pairs:
                print(cnt[u] + cnt[v] - 1)
                return

        print(cnt[u] + cnt[v] - 2)
    else:
        for i in range(len(h)):
            for j in range(i + 1, len(h)):
                if (i, j) not in pairs:
                    print(cnt[u] + cnt[v] - 1)
                    return

        print(cnt[u] + cnt[v] - 2)


for _ in range(get_int()):
    solve()


Submission (verdict: Accepted):
import io
import os
import sys


inf = 10 ** 18
mod = 10 ** 9 + 7

ONLINE_JUDGE = __debug__

if ONLINE_JUDGE:
    R = io.BytesIO(os.read(0, os.fstat(0).st_size)).readline


    def _input() -> str:
        return R().decode()
else:
    R = sys.stdin.readline


    def _input() -> str:
        return R()


def get_int() -> int:
    return int(_input())


def get_str() -> str:
    return _input().strip()


def get_int_list() -> list[int]:
    return list(map(int, _input().strip().split()))


def init_matrix(n_, m_, value_=0) -> list[list]:
    return [[value_] * m_ for _ in range(n_)]


def solve() -> None:
    n = get_int()

    g = init_matrix(n, 0)
    cnt = [0] * n
    pairs = set()
    for i in range(n - 1):
        u, v = get_int_list()
        u -= 1
        v -= 1
        g[v].append(u)
        g[u].append(v)
        cnt[u] += 1
        cnt[v] += 1
        pairs.add((u, v))
        pairs.add((v, u))

    order = sorted(
        range(len(cnt)),
        key=lambda x: cnt[x],
        reverse=True,
    )
    u, v = order[:2]
    h = []
    for i in range(n):
        if cnt[i] == cnt[v]:
            h.append(i)

    if cnt[u] != cnt[v]:
        for w in h:
            if (u, w) not in pairs:
                print(cnt[u] + cnt[v] - 1)
                return

        print(cnt[u] + cnt[v] - 2)
    else:
        for i in range(len(h)):
            for j in range(i + 1, len(h)):
                if (h[i], h[j]) not in pairs:
                    print(cnt[u] + cnt[v] - 1)
                    return

        print(cnt[u] + cnt[v] - 2)


for _ in range(get_int()):
    solve()