5df3bb4e40
Since I did not pass my one-site interview with DM, but I have been invited to attempt again, I decided to partition this directory into two parts: 1. part_one: Hosting the exercises that I completed before my first attempt at earning the job. 2. part_two: Hosting the exercise that I will complete before my second attempt at earning the job.
56 lines
1.3 KiB
Python
56 lines
1.3 KiB
Python
import unittest
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from itertools import permutations
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class Node(object):
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def __init__(self, x):
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self.value = x
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self.children = []
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def make_tree(c, xs):
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root = Node(c)
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for x in xs:
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root.children.append(make_tree(x, xs - {x}))
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return root
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def get_permutations(xs):
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xs = set(xs)
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root = make_tree("", xs)
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q, perms = [], set()
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q.append(("", root))
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while q:
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c, node = q.pop()
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if not node.children:
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perms.add(c)
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else:
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for child in node.children:
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q.append((c + child.value, child))
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return perms
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# Tests
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class Test(unittest.TestCase):
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def test_empty_string(self):
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actual = get_permutations('')
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expected = set([''])
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self.assertEqual(actual, expected)
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def test_one_character_string(self):
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actual = get_permutations('a')
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expected = set(['a'])
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self.assertEqual(actual, expected)
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def test_two_character_string(self):
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actual = get_permutations('ab')
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expected = set(['ab', 'ba'])
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self.assertEqual(actual, expected)
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def test_three_character_string(self):
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actual = get_permutations('abc')
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expected = set(['abc', 'acb', 'bac', 'bca', 'cab', 'cba'])
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self.assertEqual(actual, expected)
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unittest.main(verbosity=2)
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