AtCoder ARC #049 B - 高橋ノルム君

arc049-b.rb

N = gets.chomp.to_i
x = []
y = []
c = []
N.times do
  x_, y_, c_ = gets.chomp.split(" ").map(&:to_f)
  x << x_
  y << y_
  c << c_
end
low = 0.0
high = 10**8
mid = (low + high) / 2
(2<<6).times do
  l = []
  r = []
  u = []
  b = []
  N.times do |i|
    w = mid / c[i]
    l << x[i] - w
    r << x[i] + w
    u << y[i] + w
    b << y[i] - w
  end
  if l.max <= r.min && b.max <= u.min
    high = mid
  else
    low = mid
  end
  mid = (low + high) / 2
end
puts mid