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 C# (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace AizuOnlineJudge
{
    class Program
    {
        static void Main(string[] args)
        {
            var arr = Console.ReadLine().Split(' ').Select(double.Parse).ToArray();
            double dx = arr[2] - arr[0];
            double dy = arr[3] - arr[1];
            Console.WriteLine($"{Math.Sqrt(dx * dx + dy * dy):0.000000000}");
        }
    }
}