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MathNet 2019-part-01 — 184 problems (EN–VI) Question 80

Math Olympiad Vault · MathNet 2019-part-01 — 184 problems (EN–VI)

Question 80

In a directed graph $G$ outgoing degree of each vertex equals $3$ (loops and bidirectional edges are allowed and considered as cycles). Prove that the graph contains $2$ non-intersecting directed cycles.