确定两个时间范围是否重叠

Question

我正在使用算法编写调度程序。在算法的最后阶段，我需要查看时间表（创建的时间表）以查看学生当时是否已被分配到班级。

因此，我们有：

Current Class Start Time: (2017, 02, 09, 10, 00, 00)
Current Class Finish Time: (2017, 02, 09, 11, 00, 00)

此时我们就通过查询时间表来查看A同学被分配到的其他班级：

例如，假设在他们已被分配的同一日期：

Class 'Z' Start Time: (2017, 02, 09, 09, 00, 00)
Class 'Z' Finish Time: (2017, 02, 09, 12, 00, 00)

现在我想找到'Z'班级的时间范围并将其与当前班级的时间范围进行比较。

DateTime startClassZ = new DateTime(2017, 02, 09, 09, 00, 00);
DateTime endClassZ = new DateTime(2017, 02, 09, 12, 00, 00);

DateTime StartCurrent = new DateTime(2017, 02, 09, 10, 00, 00);
DateTime StartCurrent = new DateTime(2017, 02, 09, 11, 00, 00);

if (They do not clash)
{
   Assign
}
if (Clash)
{
   Select Another Student
}

谁能帮我解决我的“IF 语句”以及如何解决这个问题。

按照我的想法，有以下三种可能：

1. 如果“当前班级”（开始和结束时间）位于“Z 级”（冲突 1）之间
2. 如果“当前班级”的“开始时间”落在“Z 级”之间（冲突 2）
3. 如果“当前班级”的“结束时间”落在“Z 级”之间（冲突 3）

谢谢

Answer 1

这是最简单的方法：

public static bool HasOverlap(DateTime start1, DateTime end1, DateTime start2, DateTime end2)
{
    return start1 < end2 && end1 > start2;
}

或者，如果日期不一定是正确的开始/结束顺序：

public static bool HasOverlap(DateTime start1, DateTime end1, DateTime start2, DateTime end2)
{
    return Min(start1, end1) < Max(start2, end2) && Max(start1, end1) > Min(start2, end2);
}

public static DateTime Max(DateTime d1, DateTime d2)
{
    return d1 > d2 ? d1 : d2;
}

public static DateTime Min(DateTime d1, DateTime d2)
{
    return d2 > d1 ? d1: d2;
}

请注意，如果一堂课以 2 结束，下一堂课以 2 开始，则不会有重叠。既然你在谈论课程，我假设这就是你想要的。

测试你的例子：

static void Main(string[] args)
{
    DateTime startClassZ = new DateTime(2017, 02, 09, 09, 00, 00);
    DateTime endClassZ = new DateTime(2017, 02, 09, 12, 00, 00);

    DateTime StartCurrent = new DateTime(2017, 02, 09, 10, 00, 00);
    DateTime EndCurrent = new DateTime(2017, 02, 09, 11, 00, 00);


    if(HasOverlap(startClassZ, endClassZ, StartCurrent, EndCurrent))
    {
        Console.WriteLine("clash");
    }
    else
    {
        Console.WriteLine("yay");
    }
    Console.Read();
}

我为您添加了一些快速测试：

public static void Test1()
{
    // Class A overlaps class B
    DateTime aStart = DateTime.Parse("2017-01-01T09:00:00");
    DateTime aEnd = DateTime.Parse("2017-01-01T10:00:00");

    DateTime bStart = DateTime.Parse("2017-01-01T09:30:00");
    DateTime bEnd = DateTime.Parse("2017-01-01T11:00:00");

    bool isCorrect = HasOverlap(aStart, aEnd, bStart, bEnd) == true;
    Console.WriteLine($"1: {isCorrect}");
}

public static void Test2()
{
    // Class A "surrounds" class B
    DateTime aStart = DateTime.Parse("2017-01-01T09:00:00");
    DateTime aEnd = DateTime.Parse("2017-01-01T15:00:00");

    DateTime bStart = DateTime.Parse("2017-01-01T09:30:00");
    DateTime bEnd = DateTime.Parse("2017-01-01T11:00:00");

    bool isCorrect = HasOverlap(aStart, aEnd, bStart, bEnd) == true;
    Console.WriteLine($"2: {isCorrect}");
}

public static void Test3()
{
    // Class B "surrounds" class A
    DateTime aStart = DateTime.Parse("2017-01-01T09:30:00");
    DateTime aEnd = DateTime.Parse("2017-01-01T11:00:00");

    DateTime bStart = DateTime.Parse("2017-01-01T09:00:00");
    DateTime bEnd = DateTime.Parse("2017-01-01T15:00:00");

    bool isCorrect = HasOverlap(aStart, aEnd, bStart, bEnd) == true;
    Console.WriteLine($"3: {isCorrect}");
}

public static void Test4()
{
    // Class A is before Class B
    DateTime aStart = DateTime.Parse("2017-01-01T09:00:00");
    DateTime aEnd = DateTime.Parse("2017-01-01T11:00:00");

    DateTime bStart = DateTime.Parse("2017-01-01T11:00:00");
    DateTime bEnd = DateTime.Parse("2017-01-01T12:00:00");

    bool isCorrect = HasOverlap(aStart, aEnd, bStart, bEnd) == false;
    Console.WriteLine($"4: {isCorrect}");
}

public static void Test5()
{
    // Class A is after Class B
    DateTime aStart = DateTime.Parse("2017-01-01T12:00:00");
    DateTime aEnd = DateTime.Parse("2017-01-01T14:00:00");

    DateTime bStart = DateTime.Parse("2017-01-01T11:00:00");
    DateTime bEnd = DateTime.Parse("2017-01-01T12:00:00");

    bool isCorrect = HasOverlap(aStart, aEnd, bStart, bEnd) == false;
    Console.WriteLine($"5: {isCorrect}");
}

public static void Test6()
{
    // Class B overlaps class A
    DateTime bStart = DateTime.Parse("2017-01-01T09:00:00");
    DateTime bEnd = DateTime.Parse("2017-01-01T10:00:00");

    DateTime aStart = DateTime.Parse("2017-01-01T09:30:00");
    DateTime aEnd = DateTime.Parse("2017-01-01T11:00:00");

    bool isCorrect = HasOverlap(aStart, aEnd, bStart, bEnd) == true;
    Console.WriteLine($"6: {isCorrect}");
}

static void Main()
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();
    Test6();
    Console.Read();
}