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Official Analysis (C++)

Video Solution

By Arpan Banerjee

Bonus (Silver level)

Suppose that instead of cow $i$ passing to the nearest cow, cow $i$ passes to cow $p_i$ where the array $a_1,a_2,\dots,a_N$ is given as input ($1\le a_i\le N$). In other words, the passing graph can be any functional graph.

Solve the problem in $O(N)$ time.