Problem:
Distance

Write a program which calculates the distance between two points P1(x1, y1) and P2(x2, y2).

Input

Four real numbers x1, y1, x2 and y2 are given in a line.

Output

Print the distance in real number. The output should not contain an absolute error greater than 10-4.

Sample Input

0 0 1 1

Sample Output

1.41421356

Solution in Ruby (judge verdict: Wrong Answer)

def calc_distance(x, y) #x, y???????´???°2??????1?¬??????????
  require 'bigdecimal'
  distance = ((y[0] - x[0])**2 + (y[1] - x[1])**2) ** 0.5
  distance_approximately = BigDecimal(distance.to_s).floor(8).to_f
  return distance_approximately #P1??¨P2????????¢
end

x = [0, 0]
y = [1, 1]

puts calc_distance(x, y)