53 lines
1.1 KiB
Python
53 lines
1.1 KiB
Python
import sys
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import math
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def main():
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n = int(input())
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people = {}
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for i in range(n):
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xi, yi = [int(j) for j in input().split()]
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pxi = people.setdefault(xi, set())
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pyi = people.setdefault(yi, set())
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pxi.add(yi)
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pyi.add(xi)
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# perr('people', people)
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min_length = math.inf
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# perr('people', people)
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for start in people:
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res = {}
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dfs3(people, start, res)
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# perr('res', res)
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inner_max_length = max(res.values())
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if inner_max_length < min_length:
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min_length = inner_max_length
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print(min_length)
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def dfs3(graph: dict, start: str, res: dict, depth: int = 0, visited: set = None) -> None:
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if visited is None:
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visited = set()
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visited.add(start)
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depth += 1
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nxt = set(graph.get(start, [])) - visited
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for succ in nxt:
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distance = res.get(succ)
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if (distance and depth < distance) or not distance:
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res[succ] = depth
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dfs3(graph, succ, res, depth, visited)
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def perr(*values):
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print(*values, file=sys.stderr)
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if __name__ == '__main__':
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main()
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