2020校招4399游戏开发岗笔试编程题（C#）

一、 小球自由落体，一球从100米高度自由落下，每次落地后反跳回原高度的一半；再落下，求它在第n次落地时，共经过多少米？第n次反弹多高？

using System;
struct Value
{
    public double sum;
    public double hight;
}
class Program
{
    public static void Main(string[] str)
    {
        int key = int.Parse(Console.ReadLine());
        Value value = new Value();
        value = Program.Ra(key);
        Console.WriteLine($"{value.sum} {value.hight}");
    }
    public static Value Ra(int key)
    {
        double tempN = 100;
        Value value = new Value();
        for (int i = 0; i < key; i++)
        {
            value.sum += tempN * 2;
            tempN *= 0.5f;
        }
        value.sum -= 100;
        value.hight = tempN;
        return value;
    }
}

二、有n个人围成一圈，顺序排号。从第一个人开始报数（从1到3报数），凡报到3的人退出圈子，问最后留下的是原来第几号的那位。

using System;
using System.Collections.Generic;
using System.Linq;

struct Person
{
    public int number;
    public int sort;
}
class Program
{
    public static void Main(string[] str)
    {
        int key = int.Parse(Console.ReadLine());
        Person person = new Person();
        person = Program.Ra(key);
        Console.WriteLine($"{person.number}");
    }
    public static Person Ra(int key = 1)
    {
        Person[] people = new Person[key];
        for (int i = 0; i < key; i++)
        {
            people[i].number = i + 1;
        }
        int order = 1;
        while (people.Length > 1)
        {
            for (int i = 0; i < people.Length; order++, i++)
            {
                people[i].sort = order;
            }
            //LINQ语言：写法一
            //IEnumerable<Person> newPeople = from val in people
            //                                where val.sort % 3 != 0
            //                                select val;
            //people = newPeople.ToArray();

            //LINQ语言：写法二
            people = people.Where(val => val.sort % 3 != 0).ToArray();
        }
        return people[0];
    }
}

三、小陆每天要写一份工作日报，日报标题含有日期。几年后，他翻开以前的日报，想知道两份日报的日期是否同为星期几，请编程帮助他判断。

using System;
struct CompareDate
{
    public int year1;
    public int month1;
    public int day1;
    public int week1;
    public int year2;
    public int month2;
    public int day2;
    public int week2;
}
class Program
{
    public static void Main(string[] str)
    {
        int group = int.Parse(Console.ReadLine());
        CompareDate[] compareDate = new CompareDate[group];
        for (int i = 0; i < group; i++)
        {
            string[] inputs = Console.ReadLine().Split("".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
            compareDate[i].year1 = int.Parse(inputs[0]);
            compareDate[i].month1 = int.Parse(inputs[1]);
            compareDate[i].day1 = int.Parse(inputs[2]);
            compareDate[i].year2 = int.Parse(inputs[3]);
            compareDate[i].month2 = int.Parse(inputs[4]);
            compareDate[i].day2 = int.Parse(inputs[5]);
        }
        for (int i = 0; i < group; i++)
        {
            Console.WriteLine($"{Compare(compareDate[i])}");
        }
    }
    public static bool Compare(CompareDate compareDate)
    {
        compareDate.week1 = WeekValue(compareDate.year1, compareDate.month1, compareDate.day1);
        compareDate.week2 = WeekValue(compareDate.year2, compareDate.month2, compareDate.day2);
        return compareDate.week1 == compareDate.week2;
    }
    public static int WeekValue(int year = 0, int month = 0, int day = 0)
    {
        if (month == 1 || month == 2)
        {
            month += 12;
            year--;
        }
        int week = (day + 2 * month + 3 * (month + 1) / 5 + year + year / 4 - year / 100 + year / 400) % 7;
        return week;
    }
}

四、段誉身具凌波微波，动无常则，若危若安，一次能走一级台阶或者两级台阶，他要爬一段30级的山路，问有多少种走法？分析如何计算，然后编程解答。
进阶问题：当他轻功熟练度提升，一次最多可以走三级，那就结果有什么变化？后来走火入魔了，不能走一级，只能走二或三级，又有什么变化？

using System;
class Program
{
    public static void Main(string[] str)
    {
        int hierarchy = int.Parse(Console.ReadLine());

        Console.WriteLine($"{Condition1(hierarchy)} {Condition2(hierarchy)} {Condition3(hierarchy)}");
    }
    public static int Condition1(int hierarchy)
    {
        if (hierarchy == 0) return 1;
        if (hierarchy < 0) return 0;
        return Condition1(hierarchy - 1) + Condition1(hierarchy - 2);
    }
    public static int Condition2(int hierarchy)
    {
        if (hierarchy == 0) return 1;
        if (hierarchy < 0) return 0;
        return Condition2(hierarchy - 1) + Condition2(hierarchy - 2) + Condition2(hierarchy - 3);
    }
    public static int Condition3(int hierarchy)
    {
        if (hierarchy == 0) return 1;
        if (hierarchy < 0) return 0;
        return Condition3(hierarchy - 2) + Condition3(hierarchy - 3);
    }
}