2019 day 16 complete

2019/d16.py

@@ -40,7 +40,7 @@ def phase_with_offset(digits_in, pattern, offset):
     digits_out = digits_in.copy()
     for round in range(offset, len(digits_in)):
         i, out = 0, 0
-        print(round)
+        # print(round)
 
         pattern_value = pattern[((i + 1) // (round + 1)) % len(pattern)]
         if pattern_value == 0:
@@ -53,8 +53,6 @@ def phase_with_offset(digits_in, pattern, offset):
                 out += pattern_value * sum(
                     digits_in[i : min(i + 1 + round, len(digits_in))]
                 )
-                # for j in range(i, min(i + 1 + round, len(digits_in))):
-                #     out += (pattern_value * digits_in[j])
             i += round + 1
 
         out = abs(out) % 10
@@ -71,16 +69,33 @@ def part_1(data):
         input = phase_with_offset(input, pattern, 0)
     print("".join(map(str, input[:8])))
 
-    input = list(map(int, (data.strip()))) * 10_000
-    offset = int("".join(map(str, input[:7]))) - 200
+    out = list(map(int, (data.strip()))) * 10_000
+    offset = int("".join(map(str, out[:7])))
+    for _ in range(100):
+        for i in range(len(out) - 2, len(out) - 1_000_000, -1):
+            out[i] = abs(out[i] + out[i + 1]) % 10
+    print("".join(map(str, out[offset : offset + 8])))
 
-    for i in range(100):
-        print(i)
-        input = phase_with_offset(input, pattern, offset)
-    print(input)
-
-    return
+    # digits = 40
+    # for round in range(digits):
+    #     s = ""
+    #     for i in range(digits):
+    #         pattern_i = ((i + 1) // (round + 1)) % len(pattern)
+    #         pattern_value = pattern[pattern_i]
+    #         if pattern_value == 0:
+    #             s += " "
+    #         elif pattern_value == 1:
+    #             s += "+"
+    #         elif pattern_value == -1:
+    #             s += "-"
+    #         else:
+    #             assert False
+    #     print(s)
+    # return
 
+    # Just here to document my thought process. Mental hack: Assume that you
+    # have the capability to solve the problem easily.
+    #
     # What do I know?
     #
     # 1. There is a solution. Other people have solved it.

README.md

@@ -127,7 +127,7 @@ Solutions and utility script for Advent of Code challenges in Python.
 - Day 13: >120:00 (Just struggling so much for some reason.)
 - Day 14: >120:00 (Hmm, wasn't that hard either.)
 - Day 15: >120:00 (I am really weak at the moment.)
-- Day 16:
+- Day 16: days    (Wow. Just too hard for me to solve quickly?)
 - Day 17: days    (Fun but too tricky for me to be fast.)
 - Day 18:
 - Day 19: 40:00 (Way too slow! Oversight error. Come on.)