ARC#004 A問題

gistfile1.rb

#! /usr/bin/env ruby
# coding: utf-8

n = STDIN.gets.to_i
x = []
y = []
(0 ... n).each do |i|
  x[i], y[i] = STDIN.gets.strip.split(' ')
  x[i] = x[i].to_i
  y[i] = y[i].to_i
end

max = 0
(0 ... n).each do |i|
  (0 ... n).each do |j|
    next if i == j
    len = Math.sqrt((x[i] - x[j]).abs ** 2 + (y[i] - y[j]).abs ** 2)
    max = len if max < len
  end
end

print "#{max}\n"