64 lines
1.6 KiB
Python
64 lines
1.6 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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# is_valid :: String -> Boolean
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def is_valid(xs):
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s = []
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seeking = {
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'}': '{',
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']': '[',
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')': '(',
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}
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openers = seeking.values()
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closers = seeking.keys()
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for c in xs:
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if c in openers:
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s.append(c)
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elif c in closers:
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if not s:
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return False
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elif s[-1] != seeking.get(c):
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return False
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else:
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s.pop()
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return len(s) == 0
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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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def test_valid_short_code(self):
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result = is_valid('()')
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self.assertTrue(result)
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def test_valid_longer_code(self):
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result = is_valid('([]{[]})[]{{}()}')
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self.assertTrue(result)
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def test_interleaved_openers_and_closers(self):
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result = is_valid('([)]')
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self.assertFalse(result)
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def test_mismatched_opener_and_closer(self):
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result = is_valid('([][]}')
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self.assertFalse(result)
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def test_missing_closer(self):
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result = is_valid('[[]()')
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self.assertFalse(result)
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def test_extra_closer(self):
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result = is_valid('[[]]())')
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self.assertFalse(result)
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def test_empty_string(self):
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result = is_valid('')
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self.assertTrue(result)
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unittest.main(verbosity=2)
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