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POParsing a Multi - Tree from a string
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copied!<p>I am trying to parse a Multi - Tree from a String. </p> <hr> <p>The Syntax :</p> <p><strong>root</strong>(Tree,Tree,Tree ...) =</p> <p><img src="https://i.stack.imgur.com/VPEBE.jpg" alt="enter image description here"></p> <p>For example : </p> <p>1(2,3,4(5,3),4(7,8,5)) = </p> <p><img src="https://i.stack.imgur.com/UVLv2.jpg" alt="enter image description here"></p> <hr> <p>I figured out how to parse binary trees from strings:</p> <p>My Code :</p> <pre><code>Public Class Tree Public l As Tree = Nothing Public r As Tree = Nothing Public value As String Public Sub New(ByVal Str As String) If Str = "" Then Throw New Exception("Input String is Nothing ("""")") Dim Error_Report As String = RunCheck(Str) If Not Error_Report = "" Then Throw New Exception(Error_Report) If Str.Contains("(") Then Try value = Str.Substring(0, Str.IndexOf("(")) BulidTreeByInTo(Str.Substring(Str.IndexOf("(") + 1, Str.Length - 2 - Str.IndexOf("(")), l, r) Catch ex As Exception Throw ex End Try Else value = Str End If End Sub Private Function RunCheck(ByVal str As String) As String Dim Open_Close As Integer = 0 For i = 0 To str.Length - 1 Step 1 If str(i).ToString = "(" Then Open_Close += 1 ElseIf str(i).ToString = ")" Then Open_Close -= 1 End If If i >= 1 Then If (str(i - 1).ToString = ")" And str(i).ToString = "(") Or (str(i - 1).ToString = "(" And str(i).ToString = ")") Then Return "Error in bracket At Index " & i End If If (str(i - 1).ToString = "(" And str(i).ToString = ",") Or (str(i - 1).ToString = "," And str(i).ToString = ")") Or (str(i - 1).ToString = "," And str(i).ToString = "(") Or (str(i - 1).ToString = "," And str(i).ToString = ",") Then Return "Error in Comma At Index " & i End If End If Next If Not Open_Close = 0 Then Return "Not all existing brackets are Closed" Return "" End Function Private Function GetTheSameLevel(ByVal s As String) As Integer Dim level As Integer = 0 For i = 0 To s.Length - 1 Step 1 If s(i).ToString = "," And level = 0 Then Return i End If If s(i).ToString = "(" Then level += 1 End If If s(i).ToString = ")" Then level -= 1 End If Next Return -1 End Function Private Sub BulidTreeByInTo(ByVal str As String, ByRef l1 As Tree, ByRef r1 As Tree) Dim MiddleIndex As Integer = GetTheSameLevel(str) Dim p1 As String = str.Substring(0, MiddleIndex) Dim p2 As String = str.Substring(MiddleIndex + 1, str.Length - 1 - MiddleIndex) Try If p1.Contains("(") Then If Not p1.Substring(0, p1.IndexOf("(")).ToString = "\" Then l1 = New Tree(p1.Substring(0, p1.IndexOf("("))) BulidTreeByInTo(p1.Substring(p1.IndexOf("(") + 1, p1.Length - 2 - p1.IndexOf("(")), l1.l, l1.r) End If Else If Not p1 = "\" Then l1 = New Tree(p1) End If End If If p2.Contains("(") Then If Not p2.Substring(0, p2.IndexOf("(")).ToString = "\" Then r1 = New Tree(p2.Substring(0, p2.IndexOf("("))) BulidTreeByInTo(p2.Substring(p2.IndexOf("(") + 1, p2.Length - 2 - p2.IndexOf("(")), r1.l, r1.r) End If Else If Not p2 = "\" Then r1 = New Tree(p2) End If End If Catch ex As Exception Throw ex End Try End Sub End Class </code></pre>

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