61 lines
1.8 KiB
Python
61 lines
1.8 KiB
Python
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import unittest
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################################################################################
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# Solution
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################################################################################
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def delete_node(x):
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if not x.next:
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raise Exception('Cannot delete the last node in a linked list.')
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else:
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x.value = x.next.value
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x.next = x.next.next
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################################################################################
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# Tests
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################################################################################
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class Test(unittest.TestCase):
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class LinkedListNode(object):
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def __init__(self, value, next=None):
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self.value = value
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self.next = next
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def get_values(self):
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node = self
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values = []
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while node is not None:
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values.append(node.value)
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node = node.next
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return values
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def setUp(self):
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self.fourth = Test.LinkedListNode(4)
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self.third = Test.LinkedListNode(3, self.fourth)
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self.second = Test.LinkedListNode(2, self.third)
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self.first = Test.LinkedListNode(1, self.second)
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def test_node_at_beginning(self):
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delete_node(self.first)
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actual = self.first.get_values()
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expected = [2, 3, 4]
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self.assertEqual(actual, expected)
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def test_node_in_middle(self):
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delete_node(self.second)
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actual = self.first.get_values()
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expected = [1, 3, 4]
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self.assertEqual(actual, expected)
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def test_node_at_end(self):
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with self.assertRaises(Exception):
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delete_node(self.fourth)
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def test_one_node_in_list(self):
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unique = Test.LinkedListNode(1)
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with self.assertRaises(Exception):
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delete_node(unique)
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unittest.main(verbosity=2)
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