unit6 pro4 solved

Author: yyl

unit6/.pro4.py.swp

@@ -0,0 +1,21 @@
+from opus7.tree import Tree
+
+class treeCompare(Tree):
+
+  def _compareTo(self, obj):
+    assert isInstance(self, obj.__class__)
+    if self.isEmpty:
+      if obj.isEmpty:
+        return 0
+      else:
+        return -1
+    elif obj.isEmpty:
+      return 1
+    else:
+      result = cmp(self._key, obj._key)
+      i = 0
+      while result == 0 and i < self.degree:
+        result = cmp(self.getSubtree(i), obj.getSubtree(i))
+        i += 1
+      return result
+