brackets.py

# -*- coding: utf-8 -*-
# http://www.checkio.org/mission/brackets/
# 普通こうでは!?

from itertools import dropwhile

pairs = '{} [] ()'.split()

def parse_term(s):
    t = ''.join(dropwhile(str.isdigit, s))
    if s != t:
        return t
    for pair in pairs:
        if t[0] == pair[0]:
            t = parse_expr(t[1:])
            if t[0] == pair[1]:
                return t[1:]
    raise Exception('term')

def parse_expr(s):
    s = parse_term(s)
    while True:
        if s == '' or s[0] not in '+-/*':
            return s
        s = parse_term(s[1:])

def checkio(s):
    try:
        if '' == parse_expr(s):
            return True
    except:
        pass
    return False

checkio("((5+3)*2+1)") == True
checkio("{[(3+1)+2]+}") == False
checkio("(3+{1-1)}") == False
checkio("[1+1]+(2*2)-{3/3}") == True
checkio("(({[(((1)-2)+3)-3]/3}-3)") == False