day_18a.py

#!/usr/bin/python3
from collections import deque


def getExpr(line):
    expr = deque()
    for char in line:
        if char != " ":
            expr.append(char)
    return expr


def getSubExpr(expr):
    bracket_count = 0
    expr.popleft()
    new_expr = deque()
    while bracket_count > 0 or expr[0] != ")":
        if expr[0] == "(":
            bracket_count += 1
        elif expr[0] == ")":
            bracket_count -= 1
        new_expr.append(expr[0])
        expr.popleft()
    expr.popleft()
    return new_expr


def calcExprValue(expr):
    while len(expr) > 1:
        operand1 = int()
        operand2 = int()
        if expr[0] != "(":
            operand1 = int(expr.popleft())
        else:
            operand1 = calcExprValue(getSubExpr(expr))

        operator = expr.popleft()

        if expr[0] != "(":
            operand2 = int(expr.popleft())
        else:
            operand2 = calcExprValue(getSubExpr(expr))

        if operator == "+":
            expr.appendleft(str(operand1 + operand2))
        elif operator == "*":
            expr.appendleft(str(operand1 * operand2))
    return int(expr[0])


def main():
    f = open("../input/day_18_input")
    sum = 0
    for line in f:
        line = line.strip("\n")
        expr = getExpr(line)
        sum += calcExprValue(expr)
    print(sum)


if __name__ == "__main__":
    main()