# Prove: cover time for directed graph is exponential

How can I prove that the cover time for a directed graph G can be exponential in the size of G?

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What is the "cover time"? –  Raphael Jun 22 '12 at 14:57
I think cover time means the expected number of steps taken by a random walk to visit every vertex. –  Juho Jun 22 '12 at 21:19
You also have to assume that the graph is strongly connected. –  Yuval Filmus Jan 27 '13 at 6:38