q4.py

# Provide user with current URL location
import os
import copy

path = os.getcwd()
# print(path)
print("If the file is not parsing properly, please delete any blank lines at the end and try again. Thanks :)")
print()


def load_dimacs():
    clause_set = []
    # Take url as input and read associated DIMACS file
    url = input("Enter url of DIMACS file (including .txt extension): ")

    # Interpret user input to reduce chance of error
    if url[-4:] != ".txt":
        url = url + ".txt"

    if url[0] != "\\":
        url = "\\" + url

    url = path + url

    f = open(url, "r")
    data = f.read()
    sat_list = data.split("\n")
    f.close()

    # Parse each line of DIMACS file as CNF
    i = 0
    while i < len(sat_list):
        # Ignore blank lines
        if not sat_list[i]:
            i += 1
            continue
        # Ignore non-comment lines
        elif sat_list[i][0] == "c":
            i += 1
            continue
        # Ignore problem line
        elif sat_list[i][0] == "p":
            i += 1
            continue

        # Split SAT line by space
        expression = sat_list[i].split()

        # If a 0 is at the end of a line the expression is not finished, so read the next line
        while expression[-1] != "0":
            i += 1
            expression += sat_list[i].split()
            if expression[-1] == "0":
                break

        # Remove end 0 and append to clause set
        expression.pop()
        clause_set.append(expression)

        i += 1

    clause_set_format = copy.deepcopy(clause_set)
    clause_set_format = [list(map(int, i)) for i in clause_set_format]

    return clause_set_format


clauses = load_dimacs()
print("Output clause set: " + str(clauses))