Day 16

2019/day16.py

@@ -0,0 +1,27 @@
+import math
+
+
+def main():
+    with open("day16.txt", "rt") as input_file:
+        inputs = [int(i) for i in input_file.read().rstrip()]
+
+    p = [0, 1, 0, -1]
+    for phase_id in range(100):
+        phase_id += 1
+        print(f"Phase {phase_id}...")
+        outputs = [None] * len(inputs)
+        for index in range(len(inputs)):
+            ex_f = index + 1
+            ex_p = [p[i // ex_f] for i in range(len(p) * ex_f)]
+            while len(ex_p) < len(inputs) + 1:
+                ex_p += ex_p  # yikes
+            ex_p = ex_p[1:len(inputs) + 1]
+            out = sum(a * b for a, b in zip(inputs, ex_p))
+            outputs[index] = abs(math.fmod(out, 10))
+        inputs = outputs
+    print(f"First 8 digits: {''.join(str(int(i)) for i in inputs[:8])}")
+
+
+if __name__ == "__main__":
+    main()
+