Day 18 (glamorized)

day18/part1.py

@@ -1,11 +1,6 @@
 #!/usr/bin/env python3
-import re
 
 lines = (x.strip().replace(" ", "") for x in open("input.txt"))
-RE_PLUS = re.compile(r"\+")
-RE_MUL = re.compile(r"\*")
-RE_NUM = re.compile(r"^\d")
-RE_PAR = re.compile(r"^\((.*?)\)$")
 
 def evaluate(line):
     stack = [0]
@@ -28,4 +23,5 @@ def evaluate(line):
     stack[-1] = stack[-1]*num if op[-1] == '*' else stack[-1]+num
     return stack[0]
 
+
 print(sum(evaluate(line) for line in lines))

day18/part2.py

@@ -11,7 +11,7 @@ def calc(a, b, pop):
     return operators[pop][1](a, b)
 
 
-def pres(pop):
+def prec(pop):
     return operators.get(pop, [0])[0]
 
 
@@ -24,11 +24,11 @@ def evaluate(line):
         elif char == '(':
             stack.append(char)
         elif char == ')':
-            while pres(stack[-1]) > 0:
+            while prec(stack[-1]) > 0:
                 postfix.append(calc(postfix.pop(), postfix.pop(), stack.pop()))
-            stack.pop()  # remove (
-        elif char in "*+":
-            while pres(stack[-1]) > pres(char):
+            stack.pop()
+        elif char in operators:
+            while prec(stack[-1]) > prec(char):
                 postfix.append(calc(postfix.pop(), postfix.pop(), stack.pop()))
             stack.append(char)
             postfix.append(0)