day18

day18.py

@@ -0,0 +1,79 @@
+from functools import reduce
+
+formulas = []
+
+with open('day18/input') as reader:
+    formulas.extend(reader.read().splitlines())
+
+
+def calculate_part1(cur_formula):
+    res = None
+    op = None
+    while cur_formula:
+        v = None
+        c = cur_formula.pop(0)
+        if c == '(':
+            v = calculate_part1(cur_formula)
+        elif c == ')':
+            return res
+        elif c == '*' or c == '+':
+            op = c
+            continue
+        else:
+            v = int(c)
+
+        if res is None:
+            res = v
+        else:
+            if op == '*':
+                res *= v
+            elif op == '+':
+                res += v
+            else:
+                raise ArithmeticError
+    return res
+
+
+def calculate_part2(cur_formula):
+    res = None
+    op = None
+    mul_stack = []
+    while cur_formula:
+        v = None
+        c = cur_formula.pop(0)
+        if c == '(':
+            v = calculate_part2(cur_formula)
+        elif c == ')':
+            mul_stack.append(res)
+            res = reduce((lambda x, y: x * y), mul_stack)
+            return res
+        elif c == '+':
+            op = c
+            continue
+        elif c == '*':
+            op = c
+            mul_stack.append(res)
+            res = None
+            continue
+        else:
+            v = int(c)
+
+        if res is None:
+            res = v
+        else:
+            if op == '*':
+                raise ArithmeticError
+            elif op == '+':
+                res += v
+            else:
+                raise ArithmeticError
+    mul_stack.append(res)
+    res = reduce((lambda x, y: x * y), mul_stack)
+    return res
+
+
+total_sum_part1 = sum(map(calculate_part1, map(lambda f: [c for c in f if c != ' '], formulas)))
+print(total_sum_part1)
+
+total_sum_part2 = sum(map(calculate_part2, map(lambda f: [c for c in f if c != ' '], formulas)))
+print(total_sum_part2)