dsu

/* dsu */
constexpr int _MAXN = 2e5;

int _parent[_MAXN + 1], _size[_MAXN + 1];

void _Init() noexcept
{
    for (int i = 1; i <= _MAXN; ++i)
        _parent[i] = i, _size[i] = 1;
}
int _Find(int x) noexcept
{
    return (x == _parent[x] ? x : x = _Find(_parent[x]));
}
void _Union(int x, int y) noexcept
{
    x = _Find(x), y = _Find(y);

    if (x == y) return;

    if (_size[y] > _size[x])
        swap(x, y);

    _parent[y] = x;
    _size[x] += _size[y];
}
int _Getsize(int x) noexcept
{
    return _size[_Find(x)];
}