CSES 1676 Road Construction - Logic

$1.$ Components: Start at $n$. Decrement on successful union.

$2.$ Max size: Start at $1$.

After union, update to max of current and new component size. After each edge, output components maxSize. Time: $O(m \cdot \alpha(n))$ for $m$ edges. This is the best you can do for this problem type. Use union by size (not rank) so you always know each component's exact size from the root's stored value.