Challenge: Find a Mother Vertex in a Directed Graph

Statement

Given a directed graph as input, determine a mother vertex within it. A mother vertex in a graph $G = (V, E)$, is vertex $V$ such that all other vertices in $G$ can be reached by a path from $V$. Although a graph might feature multiple mother vertices, your goal is to identify at least one.

Constraints:

• $0 \leq$ graph.length $\leq 10^4$

• $0 \leq V, E \leq 10^3$

• $V \neq E$

• There are no repeated edges.

Examples