Added day 2016-19

Piratmac · Piratmac · commit 3dd1091faf50 · 2020-05-18T19:49:30.000+02:00
diff --git a/2016/19-An Elephant Named Joseph.py b/2016/19-An Elephant Named Joseph.py
@@ -0,0 +1,71 @@
+# -------------------------------- Input data -------------------------------- #
+import os, math
+
+test_data = {}
+
+test = 1
+test_data[test]   = {"input": 5,
+                     "expected": [3, 'Unknown'],
+                    }
+
+test += 1
+test_data[test]   = {"input": 15,
+                     "expected": ['Unknown', 'Unknown'],
+                    }
+
+test = 'real'
+test_data[test] = {"input": 3012210,
+                     "expected": ['1830117', '1417887'],
+                    }
+
+# -------------------------------- Control program execution -------------------------------- #
+
+case_to_test  = 'real'
+part_to_test  = 2
+verbose_level = 1
+
+# -------------------------------- Initialize some variables -------------------------------- #
+
+puzzle_input           = test_data[case_to_test]['input']
+puzzle_expected_result = test_data[case_to_test]['expected'][part_to_test-1]
+puzzle_actual_result   = 'Unknown'
+
+
+# -------------------------------- Actual code execution -------------------------------- #
+
+if part_to_test == 1:
+    elves = list(range(1, puzzle_input + 1))
+
+    while len(elves) > 1:
+        if len(elves) %2 == 1:
+            elves = elves[::2][1:]
+        else:
+            elves = elves[::2]
+
+    puzzle_actual_result = elves[0]
+
+else:
+    # For some reason, the value for any power of 3 is equal to itself
+    # If X is a power of 3:
+    # Numbers N from X+1 to 2*X have N-X as a result (it increases by 1)
+    # Numbers N from 2*X to 3*X-1 have 2*N-3*X as a result (it increases by 2)
+
+    # Find the power of 3 right below the puzzle input
+    power_of_3 = 3**math.trunc(math.log(puzzle_input, 3))
+
+    if puzzle_input <= 2*power_of_3:
+        puzzle_actual_result = puzzle_input - power_of_3
+    else:
+        puzzle_actual_result = puzzle_input*2 - power_of_3*3
+
+
+# -------------------------------- Outputs / results -------------------------------- #
+
+if verbose_level >= 3:
+    print ('Input : ' + puzzle_input)
+print ('Expected result : ' + str(puzzle_expected_result))
+print ('Actual result   : '   + str(puzzle_actual_result))
+
+
+
+
