taneja.py

#! /usr/bin/python3.6
import datetime
import itertools


def show_progress(start, idx, total):
    if idx == 0:
        return
    now = datetime.datetime.now()
    speed = idx / (now - start).total_seconds()
    togo = (total - idx) / speed
    eta = now + datetime.timedelta(seconds=togo)
    print(f'{now}: {idx} of {total} eta={eta} [{speed:0.4F} exp/s]')


def generate_product(lst, count):
    yield from itertools.product(*[lst] * count)


def generate_operations(count):
    operations = ['+', '-', '/', '*', '**', '']
    for ops in generate_product(operations, count):
        if ops.count('**') >= 2:
            continue
        yield ops


def generate_braces(count):
    obr = ['(', '']
    cbr = [')', '']
    for o in generate_product(obr, count):
        for c in generate_product(cbr, count):
            if o.count('(') != c.count(')'):
                continue
            yield o, c


def check_exression(exp):
    if ')(' in exp or '()' in exp:
        return
    try:
        res = eval(exp)
        if res == int(res):
            return res
    except (SyntaxError, ZeroDivisionError, TypeError, OverflowError) as e:
        pass
    except Exception as e:
        print(exp, type(e))
        pass


def generate_expression(digits):
    operations = generate_operations(len(digits) - 1)
    operations = list(operations)
    total = len(operations)
    start = datetime.datetime.now()
    for idx, ops in enumerate(operations):
        show_progress(start, idx, total)
        for open_braces, close_braces in generate_braces(len(digits) - 1):
            exp = itertools.zip_longest(open_braces, digits, close_braces, ops, fillvalue='')
            exp = sum(exp, ())
            exp = ''.join(exp)
            yield exp
    return


def main():
    digits = "123456789"
    answers = {}
    for exp in generate_expression(digits):
        res = check_exression(exp)
        if res is not None:
            answers[res] = exp

    with open('answer.txt', 'w') as f:
        for k in sorted(answers.keys()):
            if k > 0:
                f.write('%d %s\n' % (k, answers[k]))


if __name__ == '__main__':
    s = datetime.datetime.now()
    main()
    e = datetime.datetime.now()
    print(e-s)