24 number

gistfile1.py

# coding=utf-8
import copy

op_method = ['+', '-', '*', '/']


def copy_arr(old, e):
    new_buf = copy.copy(old)
    new_buf.append(e)
    return new_buf


def check_val(buf):
    code_val = ''
    for i in buf:
        code_val += str(i)

    if eval(code_val) == 24:
        print code_val


def get_num(buf):
    if len(buf) < 7:
        if len(buf) != 0 and (len(buf) - 1) % 2 == 0:
            for i in op_method:
                get_num(copy_arr(buf, i))
        else:
            for i in range(0, 9):
                if i in buf:
                    continue
                if len(buf) != 0 and buf[len(buf) - 1] is '/':
                    before_val = buf[len(buf) - 2]
                    if i == 0 or before_val % i != 0:
                        continue
                get_num(copy_arr(buf, i))
    else:
        check_val(buf)


if __name__ == '__main__':
    get_num([])