我想在VB.Net中的字符串中找到重复序列,如：
昏暗测试为String =“EDCRFVTGBEDCRFVTGBEDCRFVTGBEDCRFVTGBEDCRFVTGBEDCRFVTGBEDCRFVTGB”
我希望程序检测重复序列,以防EDCRFVTGB并计算它重复的次数.我的问题是找到字符串中的重复序列,我搜索了几种方法来做它但我没有得到解决方案,我尝试了快速排序算法,重复算法,但其中一些不能用于字符串.
我虽然创建子串并检查它们是否存在于字符串中,但我不知道如何获取子串,因为字符串上没有模式,字符串中也可能没有重复序列.
解决方法
首先检查目标字符串的一半是否重复两次.如果没有,检查字符串的三分之一是否重复三次.如果没有,检查字符串的四分之一是否重复四次.这样做直到找到匹配的序列.跳过商数不是整数的任何除数,使其表现更好.此代码应该可以解决这个问题并填写此描述无法澄清的任何空白：
Public Function DetermineSequence(ByVal strTarget As String) As String
Dim strSequence As String = String.Empty
Dim intLengthOfTarget As Integer = strTarget.Length
'Check for a valid Target string.
If intLengthOfTarget > 2 Then
'Try 1/2 of Target,1/3 of Target,1/4 of Target,etc until sequence is found.
Dim intCursor As Integer = 2
Do Until strSequence.Length > 0 OrElse intCursor = intLengthOfTarget
'Don't even test the string if its length is not a divisor (to an Integer) of the length of the target String.
If IsDividendDivisibleByDivisor(strTarget.Length,intCursor) Then
'Get the possible sequence.
Dim strPossibleSequence As String = strTarget.Substring(0,(intLengthOfTarget / intCursor))
'See if this possible sequence actually is the repeated String.
If IsPossibleSequenceRepeatedThroughoutTarget(strPossibleSequence,strTarget) Then
'The repeated sequence has been found.
strSequence = strPossibleSequence
End If
End If
intCursor += 1
Loop
End If
Return strSequence
End Function
Private Function IsDividendDivisibleByDivisor(ByVal intDividend As Integer,ByVal intDivisor As Integer) As Boolean
Dim bolDividendIsDivisbleByDivisor As Boolean = False
Dim intOutput As Integer
If Integer.TryParse((intDividend / intDivisor),intOutput) Then
bolDividendIsDivisbleByDivisor = True
End If
Return bolDividendIsDivisbleByDivisor
End Function
Private Function IsPossibleSequenceRepeatedThroughoutTarget(ByVal strPossibleSequence As String,ByVal strTarget As String) As Boolean
Dim bolPossibleSequenceIsRepeatedThroughoutTarget As Boolean = False
Dim intLengthOfTarget As Integer = strTarget.Length
Dim intLengthOfPossibleSequence As Integer = strPossibleSequence.Length
Dim bolIndicatorThatPossibleSequenceIsCertainlyNotRepeated As Boolean = False
Dim intCursor As Integer = 1
Do Until (intCursor * intLengthOfPossibleSequence) = strTarget.Length OrElse bolIndicatorThatPossibleSequenceIsCertainlyNotRepeated
If strTarget.Substring((intCursor * intLengthOfPossibleSequence),intLengthOfPossibleSequence) <> strPossibleSequence Then
bolIndicatorThatPossibleSequenceIsCertainlyNotRepeated = True
End If
intCursor += 1
Loop
If Not bolIndicatorThatPossibleSequenceIsCertainlyNotRepeated Then
bolPossibleSequenceIsRepeatedThroughoutTarget = True
End If
Return bolPossibleSequenceIsRepeatedThroughoutTarget
End Function