sgreen solutions to challenge 285

3 files changed, 87 insertions, 0 deletions

diff --git a/challenge-285/sgreen/python/ch-1.py b/challenge-285/sgreen/python/ch-1.py
new file mode 100755
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+++ b/challenge-285/sgreen/python/ch-1.py
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+#!/usr/bin/env python3
+
+import sys
+
+
+def no_connection(routes: list) -> str:
+    # Calculate a list of origins (first value) and destinations (second value)
+    origins = [v[0] for v in routes]
+    destinations = [v[1] for v in routes]
+
+    # Find route destinations that aren't also an origin
+    dead_ends = [d for d in destinations if d not in origins]
+
+    if len(dead_ends) > 1:
+        raise ValueError(
+            'There are multiple routes with no outgoing connection')
+
+    if len(dead_ends) == 0:
+        raise ValueError('All routes have an outgoing connection')
+
+    return dead_ends[0]
+
+
+def main():
+    # Convert input into pairs. The first value is the start of route.
+    # The second value is the destination
+    routes = []
+    for i in range(1, len(sys.argv), 2):
+        routes.append([sys.argv[i], sys.argv[i+1]])
+    result = no_connection(routes)
+    print(result)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/challenge-285/sgreen/python/ch-2.py b/challenge-285/sgreen/python/ch-2.py
new file mode 100755
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+++ b/challenge-285/sgreen/python/ch-2.py
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+#!/usr/bin/env python3
+
+import sys
+
+
+def making_change(remaining: int, last_coin: int | None = None) -> int:
+    combinations = 0
+
+    for coin in [1, 5, 10, 25, 50]:
+        if last_coin and last_coin < coin:
+            # We can't use a larger coin that the last one
+            continue
+        if coin == remaining:
+            # We have found a solution
+            combinations += 1
+        if coin < remaining:
+            # Call the function again, taking away the value of the coin
+            combinations += making_change(remaining-coin, coin)
+
+    # This value is returned upstream as we go
+    return combinations
+
+
+def main():
+    result = making_change(int(sys.argv[1]))
+    print(result)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/challenge-285/sgreen/python/test.py b/challenge-285/sgreen/python/test.py
new file mode 100755
index 0000000000..5ac058a985
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+++ b/challenge-285/sgreen/python/test.py
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+#!/usr/bin/env python3
+
+import unittest
+ch_1 = __import__('ch-1')
+ch_2 = __import__('ch-2')
+
+
+class TestClass(unittest.TestCase):
+    def test_ch_1(self):
+        self.assertEqual(
+            ch_1.no_connection([['B', 'C'], ['D','B'], ['C','A']]), 'A'
+        )
+        self.assertEqual(ch_1.no_connection([['A', 'Z']]), 'Z')
+
+    def test_ch_2(self):
+        self.assertEqual(ch_2.making_change(9), 2)
+        self.assertEqual(ch_2.making_change(15), 6)
+        self.assertEqual(ch_2.making_change(100), 292)
+
+
+if __name__ == '__main__':
+    unittest.main()