def test_reject_traversals_of_different_length(self):
preorder = ["a", "b"]
inorder = ["b", "a", "r"]
with self.assertRaises(ValueError) as err:
tree_from_traversals(preorder, inorder)
self.assertEqual(type(err.exception), ValueError)
self.assertEqual(err.exception.args[0],
"traversals must have the same length")
def test_reject_traversals_with_repeated_items(self):
preorder = ["a", "b", "a"]
inorder = ["b", "a", "a"]
with self.assertRaises(ValueError) as err:
tree_from_traversals(preorder, inorder)
self.assertEqual(type(err.exception), ValueError)
self.assertEqual(err.exception.args[0],
"traversals must contain unique items")
def test_reject_inconsistent_traversals_of_same_length(self):
preorder = ["x", "y", "z"]
inorder = ["a", "b", "c"]
with self.assertRaises(ValueError) as err:
tree_from_traversals(preorder, inorder)
self.assertEqual(type(err.exception), ValueError)
self.assertEqual(err.exception.args[0],
"traversals must have the same elements")
def test_tree_with_many_items(self):
preorder = ["a", "i", "x", "f", "r"]
inorder = ["i", "a", "f", "x", "r"]
expected = {
"v": "a",
"l": {
"v": "i",
"l": {},
"r": {}
},
"r": {
"v": "x",
"l": {
"v": "f",
"l": {},
"r": {}
},
"r": {
"v": "r",
"l": {},
"r": {}
}
}
}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_tree_with_many_items(self):
preorder = ["a", "i", "x", "f", "r"]
inorder = ["i", "a", "f", "x", "r"]
expected = {
"v": "a",
"l": {
"v": "i",
"l": {},
"r": {}
},
"r": {
"v": "x",
"l": {
"v": "f",
"l": {},
"r": {}
},
"r": {
"v": "r",
"l": {},
"r": {}
}
}
}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_tree_with_one_item(self):
preorder = ["a"]
inorder = ["a"]
expected = {
"v": "a",
"l": {},
"r": {}
}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_tree_with_many_more_items1(self):
preorder = ['f', 'b', 'a', 'd', 'c', 'e', 'g', 'i', 'h']
inorder = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i']
#
#
# . . . . F . . . .
# / \
# . B . . . G
# / \ \
# A . D . . . I
# / \ /
# . C . E . H
#
expected = {
"v": "f",
"l": {
"v": "b",
"l": {
"v": "a",
"l": {},
"r": {}
},
"r": {
"v": "d",
"l": {
"v": "c",
"l": {},
"r": {}
},
"r": {
"v": "e",
"l": {},
"r": {}
}
}
},
"r": {
"v": "g",
"l": {},
"r": {
"v": "i",
"l": {
"v": "h",
"l": {},
"r": {}
},
"r": {}
},
},
}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_tree_with_many_more_items2(self):
preorder = ['+', '*', 'a', '-', 'b', 'c', '/', 'd', 'e']
inorder = ['a', '*', 'b', '-', 'c', '+', 'd', '/', 'e']
expected = {
"v": "+",
"l": {
"v": "*",
"l": {
"v": "a",
"l": {},
"r": {}
},
"r": {
"v": "-",
"l": {
"v": "b",
"l": {},
"r": {}
},
"r": {
"v": "c",
"l": {},
"r": {}
}
},
},
"r": {
"v": "/",
"l": {
"v": "d",
"l": {},
"r": {}
},
"r": {
"v": "e",
"l": {},
"r": {}
},
},
}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_bigger_tree(self):
preorder = ["a", "m", "n", "o", "p", "q", "x", "f", "r"]
inorder = ["n", "m", "p", "o", "q", "a", "f", "x", "r"]
expected = {
"v": "a",
"l": {
"v": "m",
"l": {"v": "n", "l": {}, "r": {}},
"r": {
"v": "o",
"l": {"v": "p", "l": {}, "r": {}},
"r": {"v": "q", "l": {}, "r": {}},
},
},
"r": {
"v": "x",
"l": {"v": "f", "l": {}, "r": {}},
"r": {"v": "r", "l": {}, "r": {}},
},
}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_reject_inconsistent_traversals_of_same_length(self):
preorder = ["x", "y", "z"]
inorder = ["a", "b", "c"]
with self.assertRaisesWithMessage(ValueError):
tree_from_traversals(preorder, inorder)
def test_reject_traverals_of_different_length(self):
preorder = ["a", "b"]
inorder = ["b", "a", "r"]
with self.assertRaisesWithMessage(ValueError):
tree_from_traversals(preorder, inorder)
def test_tree_with_one_item(self):
preorder = ["a"]
inorder = ["a"]
expected = {"v": "a", "l": {}, "r": {}}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_empty_tree(self):
preorder = []
inorder = []
expected = {}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_reject_traverals_with_repeated_items(self):
preorder = ["a", "b", "a"]
inorder = ["b", "a", "a"]
with self.assertRaisesWithMessage(ValueError):
tree_from_traversals(preorder, inorder)
def test_reject_traverals_of_different_length(self):
preorder = ["a", "b"]
inorder = ["b", "a", "r"]
with self.assertRaisesWithMessage(ValueError):
tree_from_traversals(preorder, inorder)
def test_reject_traverals_with_repeated_items(self):
preorder = ["a", "b", "a"]
inorder = ["b", "a", "a"]
with self.assertRaisesWithMessage(ValueError):
tree_from_traversals(preorder, inorder)
def test_empty_tree(self):
preorder = []
inorder = []
expected = {}
self.assertEqual(tree_from_traversals(preorder, inorder), expected)
def test_reject_inconsistent_traversals_of_same_length(self):
preorder = ["x", "y", "z"]
inorder = ["a", "b", "c"]
with self.assertRaisesWithMessage(ValueError):
tree_from_traversals(preorder, inorder)
