vb.net - 计算同一时期发生的时间的算法

Question

我已经为这个问题制定了一个算法，但仍然遇到了麻烦。

假设我有日程安排的回顾(包含名为 GV 的 gridview):

TimeStart  TimeEnd   TotalOccuredOnThisTime
----------------------------------------------
08.00      08.50     1
08.00      09.40     43
08.00      10.50     2

请看下面的图片以获得更清晰的信息:

我想从算法中得到的是，计算同一时期内发生的时间，例如截至 08:00，发生了 46 个事件(参见黄色行)。

这是我的算法:

Dim ColumnLength As Integer = GV.Rows.Count
Dim TimeStart(ColumnLength - 1) As Integer
Dim TimeEnd(ColumnLength - 1) As Integer
Dim Total(ColumnLength - 1) As Integer

For i = 0 to ColumnLength - 1
  TimeStart(i) = Convert.ToInt32(Regex.Replace(GV.Rows(i).Cells(0).Text, ".", ""))
  TimeEnd(i) = Convert.ToInt32(Regex.Replace(GV.Rows(i).Cells(1).Text, ".", ""))
  Total(i) = 0
Next 

For i = 0 To ColumnLength - 2
  For j = 0 To ColumnLength - 1        
    If TimeEnd(i) > TimeStart(j) And ((TimeStart(i) <= TimeEnd(j)) Or (TimeStart(i) >= TimeEnd(j))) 
      Total(j) = Total(j) - Total(i)
    End If
  Next
Next

但结果是错误的值。

我想要的结果是这样的:

Time: 08.00 - 08.50   --> 46 event occured
      08.50 - 09.40   --> 46 event occured
      09.40 - 10.00   --> 45 event occured
      etc...

如何正确地做到这一点？真的需要你的帮助...

Answer 1

您可以使用 Dictionary 来跟踪时间范围，方法是将两个时间字符串连接在一起作为 Key(无需转换为整数)，然后对于该范围的每次出现，您可以使用 ojit_a 来跟踪时间范围。可以增加 Dictionary 的 Value 部分。

此外，使用此方法不需要嵌套循环，也不需要分段循环来填充开始和结束时间数组。以下算法应该提供您正在寻找的结果:

Dim columnLength As Integer = GV.Rows.Count
Dim timeRangeCount As New Dictionary(Of String, Integer)

For i = 0 to columnLength - 1
  Dim timeStart As String = GV.Rows(i).Cells(0).Text
  Dim timeEnd As String = GV.Rows(i).Cells(1).Text
  Dim key As String = String.Format("{0}-{1}", timeStart, timeEnd)

  If timeRangeCount.ContainsKey(key)
      timeRangeCount(key) += 1
  Else
      timeRangeCount(key) = 1
  End If
Next

因此，您可以通过以下方式从字典中提取时间范围 09.40 - 10.00 的计数:

Dim totalOccuredOnThisTime As Integer = timeRangeCount("09.40-10.00")

---

我已经使用类似的测试代码验证了该算法:

Dim columnLength As Integer = 6
Dim timeStart() As String = {"08.00", "08.00", "10.00", "08.00", "08.00", "10.00"}
Dim timeEnd() As String = {"08.50", "08.50", "11.00", "09.00", "08.50", "11.00"}
Dim timeRangeCount As New Dictionary(Of String, Integer)

For i = 0 to columnLength - 1
  Dim key As String = String.Format("{0}-{1}", timeStart(i), timeEnd(i))

  If timeRangeCount.ContainsKey(key)
      timeRangeCount(key) += 1
  Else
      timeRangeCount(key) = 1
  End If
Next

Console.WriteLine(timeRangeCount)

更新

阅读评论中的说明后，您仍然可以使用字典以及几个帮助器类(TimeRange、TimeRangeCounter 和 TimeRangeEqualityComparer)。但这确实让事情变得更加复杂。

第一个帮助器类用于保存精确匹配和子范围匹配的计数:

Public Class TimeRangeCounter
    Property ExactRangeMatch as Integer
    Property SubRangeMatch as Integer
End Class

第二个帮助器类用于帮助字典了解一个键(TimeRange 类型)与另一个键有何不同:

Public Class TimeRangeEqualityComparer 
    Implements IEqualityComparer(Of TimeRange)

    Public Overloads Function Equals(left As TimeRange, right As TimeRange) _
            As Boolean Implements IEqualityComparer(Of TimeRange).Equals           

        Return left.ToString = right.ToString   
    End Function

    Public Overloads Function GetHashCode(range As TimeRange) _
            As Integer Implements IEqualityComparer(Of TimeRange).GetHashCode

        return range.ToString().GetHashCode()
    End Function

End Class

第三个辅助类存储范围的开始和结束时间:

Public Class TimeRange 
    Private readonly _start
    Private readonly _end

    Public Readonly Property Start 
        Get
           return _start
        End Get
    End Property

    Public Readonly Property [End] 
        Get
           return _end
        End Get
    End Property

    Public Sub New(start As String, [end] As string)
        Me._start = start
        Me._end = [end]
    End Sub

    Public Overrides Function ToString() as String
       Return String.Format("{0}-{1}", Start, [End])
    End Function

End Class

所以使用上面的内容我们应该能够编写这个算法:

Dim columnLength As Integer = 5
Dim timeStart() As String = {"08.00", "08.00", "10.00", "08.00", "08.00"}
Dim timeEnd() As String = {"08.50", "11.50", "11.00", "09.00", "08.50"}
Dim comparer As New TimeRangeEqualityComparer()
Dim timeRangeCounts As New Dictionary(Of TimeRange, TimeRangeCounter)(comparer)

'Count exact range matches while building dictionary
For i = 0 to columnLength - 1
  Dim key As TimeRange = New TimeRange(timeStart(i), timeEnd(i))

  If timeRangeCounts.ContainsKey(key)
      timeRangeCounts(key).ExactRangeMatch += 1
  Else
      Dim counter =  New TimeRangeCounter()
      counter.ExactRangeMatch = 1
      timeRangeCounts(key) = counter
  End If        

Next           

'Count sub ranges          
For Each kvp in timeRangeCounts
    For Each key in timeRangeCounts.Keys
        If kvp.key.Start >= key.Start AndAlso _ 
           kvp.Key.End <= key.End AndAlso _
           kvp.key.ToString <> key.ToString then           

            kvp.Value.SubRangeMatch += 1
        End If
    Next
Next

Console.WriteLine(timeRangeCounts)