题解 | #搬圆桌#

using System;
using System.Collections;
using System.Collections.Generic;
public class Program {
    public static void Main() {
        string line;
        while ((line = System.Console.ReadLine ()) != null) { // 注意 while 处理多个 case
            string[] tokens = line.Split(' '); 
            int R = int.Parse(tokens[0]) * 2;//直径
            int x = int.Parse(tokens[1]);
            int y = int.Parse(tokens[2]);
            int x1 = int.Parse(tokens[3]);
            int y1 = int.Parse(tokens[4]);
            int dx = Math.Abs(x1 - x);
            int dy = Math.Abs(y1 - y);
            double dis = Math.Sqrt(Math.Pow(dx, 2) + Math.Pow(dy, 2));
            int a = (dis % R) == 0? 0: 1;
            int result = (int)(dis / R + a);
            Console.WriteLine(result);
        }
    }
}

计算两点之间直线距离，每步移动2r的距离，移动x步后有余数，则再移动一步即可，因为倒数两步可以按照三角移动，距离可以介于r到2r之间