Imports System.IO
Public Class Worker
    Public vychozi(1) As Integer
    Public cil(1) As Integer
    Public vysledek As Boolean
    Public jedubezzdi As Boolean
    Private Sub BackgroundWorker1_DoWork(sender As System.Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
        Dim ctecka As New StreamReader(soubor)
        Dim intro As String = ctecka.ReadLine
        sirka = intro.Split(" ")(0) - 1
        vyska = intro.Split(" ")(1) - 1
        max = (sirka + 1) * (vyska + 1) + 1
        Dim pole(sirka, vyska) As Char
        For i As Integer = 0 To vyska
            Dim radek As String = ctecka.ReadLine
            For j As Integer = 0 To sirka
                If radek(j) = "&" Then
                    vychozi = {i, j}
                ElseIf radek(j) = "#" Then
                    cil = {i, j}
                ElseIf radek(j) = "X" Then
                    max -= 1
                End If
                pole(i, j) = radek(j)
            Next
        Next
        ctecka.Close()
        mapa = pole

        vysledek = Hybej(vychozi, 1)
    End Sub
    Function Hybej(PraveStojim() As Integer, vrstva As Integer) As Boolean
        Dim vraceni As Boolean = False
        Dim moznosti As New List(Of Integer())
        If vrstva > max Then Return False
        If KamJsemSlapl(PraveStojim) = 1 Then
            If vrstva < max Then
                tahy.Clear()
                tahy.Add(PraveStojim)
                max = vrstva
                vraceni = True
            End If
        ElseIf KamJsemSlapl(PraveStojim) = 0 Then
            moznosti.Add({PraveStojim(0) + 1, PraveStojim(1)})
            moznosti.Add({PraveStojim(0), PraveStojim(1) + 1})
            moznosti.Add({PraveStojim(0) - 1, PraveStojim(1)})
            moznosti.Add({PraveStojim(0), PraveStojim(1) - 1})
            moznosti.Sort(AddressOf PorovnejVzdalenosti)
            For i As Integer = 0 To 3
                If Hybej(moznosti.Item(i), vrstva + 1) Then
                    tahy.Add(PraveStojim)
                    vraceni = True
                End If
            Next
        End If
        Return vraceni
    End Function
    Function KamJsemSlapl(jdina() As Integer) As Integer
        If (jdina(0) < 0) Or (jdina(0) > sirka) Or (jdina(1) < 0) Or (jdina(1) > vyska) Then 'mimo mapu
            Return -1
        ElseIf mapa(jdina(0), jdina(1)) = "X" Then 've zdi
            Return -2
        ElseIf mapa(jdina(0), jdina(1)) = "#" Then 'v cili
            Return 1
        Else 'pohoda
            Return 0
        End If
    End Function

    Private Sub Worker_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        BackgroundWorker1.RunWorkerAsync()
    End Sub

    Private Sub BackgroundWorker1_RunWorkerCompleted(sender As System.Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        If vysledek = False Then
            MsgBox("Cesta neexistuje!")
            Application.Exit()
        End If
        Dim neco As New Vykresleni
        neco.Show()
        Me.Close()
    End Sub
    Function PorovnejVzdalenosti(ByVal zajem1() As Integer, ByVal zajem2() As Integer) As Integer
        Dim prvni, druha As Integer
        prvni = Math.Abs(zajem1(0) - cil(0)) + Math.Abs(zajem1(1) - cil(1))
        druha = Math.Abs(zajem2(0) - cil(0)) + Math.Abs(zajem2(1) - cil(1))
        If prvni = druha Then
            Return 0
        Else
            Return prvni - druha
        End If
    End Function
End Class