Add InterviewCake.com examples

Adds some of the code I generated while studying for a role transfer at Google
using the fantastic resource, InterviewCake.com. This work predates the
mono-repo.

I should think of ways to DRY up this code and the code in
crack_the_coding_interview, but I'm afraid I'm creating unnecessary work for
myself that way.

1 files changed, 49 insertions, 0 deletions

diff --git a/data_structures_and_algorithms/permutation-palindrome.py b/data_structures_and_algorithms/permutation-palindrome.py
new file mode 100644
index 000000000000..0a2136a408f2
--- /dev/null
+++ b/data_structures_and_algorithms/permutation-palindrome.py
@@ -0,0 +1,49 @@
+from collections import Counter
+import unittest
+
+
+################################################################################
+# Impl
+################################################################################
+# palindromifiable :: String -> Boolean
+def has_palindrome_permutation(x):
+    bag = Counter(x)
+    odd_entries_ct = 0
+
+    for _, y in bag.items():
+        if y % 2 != 0:
+            odd_entries_ct += 1
+
+    return odd_entries_ct in {0, 1}
+
+
+################################################################################
+# Tests
+################################################################################
+class Test(unittest.TestCase):
+    def test_permutation_with_odd_number_of_chars(self):
+        result = has_palindrome_permutation('aabcbcd')
+        self.assertTrue(result)
+
+    def test_permutation_with_even_number_of_chars(self):
+        result = has_palindrome_permutation('aabccbdd')
+        self.assertTrue(result)
+
+    def test_no_permutation_with_odd_number_of_chars(self):
+        result = has_palindrome_permutation('aabcd')
+        self.assertFalse(result)
+
+    def test_no_permutation_with_even_number_of_chars(self):
+        result = has_palindrome_permutation('aabbcd')
+        self.assertFalse(result)
+
+    def test_empty_string(self):
+        result = has_palindrome_permutation('')
+        self.assertTrue(result)
+
+    def test_one_character_string(self):
+        result = has_palindrome_permutation('a')
+        self.assertTrue(result)
+
+
+unittest.main(verbosity=2)