using System;

namespace DistanceTask
{
    public static class DistanceTask
    {
        public static double GetDistanceToSegment(double ax, double ay, double bx, double by, double x, double y)
        {
            var sectionAB = Math.Sqrt((ax - bx) * (ax - bx) + (ay - by) * (ay - by));
            var sectionAC = Math.Sqrt((ax - x) * (ax - x) + (ay - y) * (ay - y));
            var sectionBC = Math.Sqrt((x - bx) * (x - bx) + (y - by) * (y - by));
            var cosABBC = ((x - ax) * (bx - ax) + (y - ay) * (by - ay)) / (sectionAC * sectionAB);
            var cosABAC = ((ax - bx) * (x - bx) + (y - by) * (ay - by)) / (sectionBC * sectionAB);
            if (Math.Round(sectionAC, 3) + Math.Round(sectionBC, 3) == Math.Round(sectionAB, 3))
            {
                return 0.0;
            }

            if ((cosABAC >= 0 && cosABAC < 1) && (cosABBC >= 0 && cosABBC < 1))
            {
                var properiter = (sectionAB + sectionAC + sectionBC) / 2; //Полусумма
                var s = Math.Sqrt(properiter * (properiter - sectionAB) *
                                  (properiter - sectionBC) *
                                  (properiter - sectionAC)); // Формула герона
                return (2 * s) / sectionAB;
            }
            return Math.Min(sectionAC, sectionBC);
        }
    }
}