From 581fa49dd5bf11105f28c97c8d0cb4afd94aaf46 Mon Sep 17 00:00:00 2001
From: Luke Hubmayer-Werner <mongoose41@gmail.com>
Date: Wed, 5 Dec 2018 17:26:54 +1030
Subject: [PATCH] Cleaned up 2018 day 5 and fixed quantum annihilation bug

---
 2018/day5.py | 70 ++++++++++++----------------------------------------
 1 file changed, 16 insertions(+), 54 deletions(-)

diff --git a/2018/day5.py b/2018/day5.py
index 3a35b9a..1eb21c7 100644
--- a/2018/day5.py
+++ b/2018/day5.py
@@ -1,59 +1,21 @@
 with open('day5-input', 'r') as file:
   data = [l.strip('\n') for l in file]
-# import numpy as np
-polymer = [c for c in reversed(data[0])]
+polymer = [c for c in data[0]]
 # polymer = [c for c in 'dabAcCaCBAcCcaDA']
 
-i = 0
-print(len(polymer))
-while i < len(polymer)-1:
-  if polymer[i] == polymer[i+1].swapcase():
-    polymer.pop(i)
-    polymer.pop(i)
-    i -= 2
-  i += 1
-print(len(polymer))  # Not 11196?!
-while i < len(polymer) - 1:
-  if polymer[i] == polymer[i + 1].swapcase():
-    polymer.pop(i)
-    polymer.pop(i)
-    i -= 2
-  i += 1
-print(len(polymer))  # Not 11196?!
-while i < len(polymer) - 1:
-  if polymer[i] == polymer[i + 1].swapcase():
-    polymer.pop(i)
-    polymer.pop(i)
-    i = -1
-  i += 1
-
-print(len(polymer))  # Part 1
-
-remaining_letters = {}
-for c in polymer:
-  c = c.lower()
-  if c in remaining_letters:
-    remaining_letters[c] += 1
-  else:
-    remaining_letters[c] = 1
-print(max(remaining_letters.items(), key=lambda x: x[1]))
-
-def react(letter):
-  polymer_2 = [c for c in data[0] if c.lower() != letter]
+def react(poly):
   i = 0
-  while i < len(polymer_2)-1:
-    if polymer_2[i] == polymer_2[i+1].swapcase():
-      polymer_2.pop(i)
-      polymer_2.pop(i)
-      i -= 2
-    i += 1
-  while i < len(polymer_2) - 1:
-    if polymer_2[i] == polymer_2[i + 1].swapcase():
-      polymer_2.pop(i)
-      polymer_2.pop(i)
-      i = -1
-    i += 1
-  return len(polymer_2)
-# print(len(polymer_2))  # Not 10658?!
-removals = [react(i) for i in remaining_letters.keys()]
-print(max(removals))  # Part 2
+  while i < len(poly)-1:
+    if poly[i] == poly[i+1].swapcase():
+      poly.pop(i+1)
+      poly.pop(i)
+      i = max(i-1, 0)
+    else:
+      i += 1
+  return poly
+
+print(len(react(list(polymer))))  # Part 1
+
+remaining_letters = set(c.lower() for c in polymer)
+removals = [len(react([c for c in polymer if c.lower() != i])) for i in remaining_letters]
+print(min(removals))  # Part 2