hats problem

dotfiles/lib/python/hats_problem.py

@@ -0,0 +1,27 @@
+import random
+
+
+class HatsProblem(object):
+
+    def __init__(self, size):
+        self.size = size
+
+    def build_hats(self):
+        return [self.hat() for _ in range(self.size)]
+
+    def hat(self):
+        return random.randint(0, self.size - 1)
+
+    def go(self):
+        hats = self.build_hats()
+        guesses = [
+            self.calculate_guess_modulus(self.sum_of_all_but_i(i, hats), i)
+            for i in range(self.size)
+        ]
+        return zip(hats, guesses)
+
+    def calculate_guess_modulus(self, current, desired):
+        return ((desired - current) + self.size) % self.size
+
+    def sum_of_all_but_i(self, i, hats):
+        return sum(hat for index, hat in enumerate(hats) if index != i)