# frozen_string_literal: true require 'bigdecimal' module Graph class Node attr_reader :id, :x, :y def initialize(id, x, y) @id = id @x = x @y = y @parent = self end def powered_length(other) (@x - other.x)**2 + (@y - other.y)**2 end def founder? @parent == self end def ancestor if founder? self else @parent.ancestor end end def same?(other) ancestor == other.ancestor end def union!(other) if founder? if ancestor.id >= other.ancestor.id @parent = other.ancestor else other.union!(self) end else @parent.ancestor.union!(other) end end end class Edge attr_reader :weight def initialize(a, b) @a = a @b = b @weight = @a.powered_length(@b) end def same? @a.same?(@b) end def union! @a.union!(@b) end end end def int_sqrt(n, k) p n BigDecimal(n).sqrt(Math.log10(n).to_i).ceil(k).to_i end n = gets.to_i list = Array.new(n) { gets.split.map(&:to_i)} node_list = list.each_with_index .map { |xy, i| Graph::Node.new(i, xy[0], xy[1]) } edge_list = node_list.product(node_list) .reject { |a, b| a == b } .map { |a, b| Graph::Edge.new(a, b) } .sort_by(&:weight) max_weight = 0 edge_list.each do |edge| break if node_list.last.ancestor == node_list.first unless edge.same? edge.union! max_weight = edge.weight end end puts int_sqrt(max_weight, -1)