21 lines
577 B
Python
21 lines
577 B
Python
def main():
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n = int(input()) # the number of relationships of influence
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influences = {}
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for i in range(n):
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# x: a relationship of influence between two people (x influences y)
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x, y = [int(j) for j in input().split()]
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influences.setdefault(x, []).append(y)
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all_lengths = [dfs(influences, x) for x in influences]
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print(max(all_lengths))
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def dfs(graph, node, depth=1):
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for succ in graph[node]:
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if succ in graph:
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return dfs(graph, succ, depth + 1)
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return depth + 1
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if __name__ == '__main__':
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main()
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