--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/defical-sharp/libbacktrack/walk.cs	Fri Apr 02 23:11:57 2010 +0700
@@ -0,0 +1,72 @@
+using System.Collections.Generic;
+
+namespace libbacktrack
+{
+    public partial class Backtrack
+    {
+        private void walk()
+        {
+            if (this.myGraph.MinDef() <= this.myGraph.NumVerDef)
+            {
+                this.isProcessing = true;
+                walk(1);
+            }
+        }
+        private void walk(int currentLevel)
+        {
+            if (this.isProcessing)
+            {
+                if (currentLevel >= this.myGraph.NumVerMain)
+                {
+                    if (this.myGraph.IsSemt())
+                    {
+                        if (!this.isRecurseAll)
+                            this.isProcessing = false;
+                        this.result += this.myGraph.Print(0);
+                        this.result += "\n" + this.myGraph.Print(1)+"\n";
+                        this.isSemt = true;
+                    }
+                    removeLabel(currentLevel - 1);
+                }
+                else
+                {
+                    List<int> availableLabels = new List<int>();
+                    int start = 1, end = this.myGraph.NumVerTotal;
+                    if (currentLevel == 1 && this.firstLabel != this.myGraph.NumVerTotal)
+                    {
+                        if (this.myGraph.GraphType == "wheel")
+                            start = end; //optimization for wheel
+                        else if (this.myGraph.GraphType == "doublefan")
+                            start = this.firstLabel + 1; //optimization for doublefan
+                    }
+                    else if (this.pathStart != 0)
+                    {
+                        if (currentLevel == this.pathEnd)
+                            start = this.pathLabel + 1; //remove possibility for reversed path labeling
+                        else if (currentLevel == this.pathStart && start < end)
+                            end = this.myGraph.NumVerTotal - 1; //no need to test last label as it'll be checked already on all previous cases
+                    }
+                    for (int i = start; i <= end; i++)
+                        if (!this.labelVerUsed[i])
+                            availableLabels.Add(i);
+                    if (availableLabels.Count > 0)
+                    {
+                        for (int x = availableLabels.Count - 1; x >= 0; x--)
+                        {
+                            if (currentLevel == this.pathStart && this.pathStart != 0)
+                                this.pathLabel = availableLabels[x];
+                            if (this.myGraph.IsValidToLabel(currentLevel, availableLabels[x]))
+                            {
+                                setLabel(currentLevel, availableLabels[x]);
+                                walk(currentLevel + 1);
+                            }
+                            if (!this.isProcessing)
+                                break;
+                        }
+                    }
+                    if (currentLevel != 1) { removeLabel(currentLevel - 1); }
+                }
+            }
+        }
+    }
+}
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