add some int-cake problems

interview_cake/palindrome.py

@@ -0,0 +1,23 @@
+"""
+Write an efficient function that checks whether 
+any permutation of an input string is a palindrome.
+"""
+
+def has_palindrome_permutation(the_string):
+    unpaired_characters = set()
+
+    for char in the_string:
+        if char in unpaired_characters:
+            unpaired_characters.remove(char)
+        else:
+            unpaired_characters.add(char)
+
+    return len(unpaired_characters) <= 1
+
+str1 = "civic"
+print has_palindrome_permutation(str1)
+print "Should be True"
+
+str2 = "ivilc"
+print has_palindrome_permutation(str2)
+print "Should be False"