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Implement min, that find the lowest node value of a tree

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Julien Lengrand-Lambert
2013-07-08 17:24:47 +02:00
parent 1b7f6206f3
commit a511bb1687
2 changed files with 57 additions and 19 deletions
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29
01_binary_search_trees/bst.py
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@@ -4,6 +4,7 @@ Binary Search Tree Implementation
2013/07
"""
class BinarySearchTree():
"""
Defines a complete binary search Tree.
@@ -24,17 +25,17 @@ class BinarySearchTree():
the node.
"""
if self.size == 0:
self.root_node = BinarySearchNode(value, None) # root node has no parent
self.root_node = BinarySearchNode(value, None) # root node has no parent
else:
node = self.root_node
is_left = None
while(node != None):
ptr_node = node # keep parent in memory
while(node is not None):
ptr_node = node # keep parent in memory
if node.value > value: # we go to the left child
node = node.left_child
is_left = True
else: # we move to the right child. This means = case too
else: # we move to the right child. This means = case too
node = node.right_child
is_left = False
@@ -52,10 +53,9 @@ class BinarySearchTree():
Returns the highest node value of the tree.
Otherwise, returns None
"""
if self.size == 0:
return None
else: # we have values in the node
else: # we have nodes in the tree
node = self.root_node
while(node.has_right_child()):
node = node.right_child
@@ -63,6 +63,22 @@ class BinarySearchTree():
# we have the leaf
return node.value
def min(self):
"""
Returns the lowest node value of the tree.
Otherwise returns None
"""
if self.size == 0:
return None
else: # we have nodes in the tree
node = self.root_node
while(node.has_left_child()):
node = node.left_child
# we have the leaf
return node.value
class BinarySearchNode():
"""
Defines any node of the Binary Search Tree.
@@ -81,4 +97,3 @@ class BinarySearchNode():
def has_right_child(self):
return self.right_child is not None

47
01_binary_search_trees/bst_test.py
View File

@@ -21,11 +21,11 @@ class test_binary_search_tree(unittest.TestCase):
self.assertEqual(bst.size, 1)
node_val2= 4
node_val2 = 4
bst.add(node_val2)
node_val3= 10
node_val3 = 10
bst.add(node_val3)
node_val4= 16
node_val4 = 16
bst.add(node_val4)
self.assertEqual(bst.size, 4)
@@ -40,11 +40,11 @@ class test_binary_search_tree(unittest.TestCase):
bst = BinarySearchTree()
node_val1 = 6
bst.add(node_val1)
node_val2= 4
node_val2 = 4
bst.add(node_val2)
node_val3= 10
node_val3 = 10
bst.add(node_val3)
node_val4= 16
node_val4 = 16
bst.add(node_val4)
self.assertEqual(bst.size, 4)
@@ -55,11 +55,10 @@ class test_binary_search_tree(unittest.TestCase):
self.assertTrue(node.has_right_child())
self.assertEqual(node.right_child.value, node_val3)
node = node.left_child # we have 4 now
node = node.left_child # we have 4 now
self.assertFalse(node.has_left_child())
self.assertFalse(node.has_right_child())
def test_max(self):
# 6
@@ -74,15 +73,39 @@ class test_binary_search_tree(unittest.TestCase):
node_val1 = 6
bst.add(node_val1)
node_val2= 4
node_val2 = 4
bst.add(node_val2)
node_val3= 10
node_val3 = 10
bst.add(node_val3)
node_val4= 16
node_val4 = 16
bst.add(node_val4)
self.assertEqual(bst.size, 4)
self.assertEqual(bst.max(), node_val4)
def test_min(self):
# 6
# / \
# 4 10
# \
# 16
bst = BinarySearchTree()
self.assertEqual(bst.min(), None)
node_val1 = 6
bst.add(node_val1)
node_val2 = 4
bst.add(node_val2)
node_val3 = 10
bst.add(node_val3)
node_val4 = 16
bst.add(node_val4)
self.assertEqual(bst.size, 4)
self.assertEqual(bst.min(), node_val2)
if __name__ == '__main__':
unittest.main()
unittest.main()