LeetCode 310 Minimum Height Trees - Problem Statement

Find the root(s) that reduce tree height. There are at most $2$ such roots, and they're the tree's centroid(s). Approach $1$: Root at each node, compute height, take minimum. $O(n^2)$ naive, $O(n)$ with rerooting.

Approach $2$: Peel leaves layer by layer. Remove all degree-$1$ nodes, repeat. The last $1$-$2$ nodes remaining are the answer. Both approaches give the centroid(s). The peeling approach is simpler and naturally handles the "at most $2$" property.