Keep Track of Brackets (interview q)

bracket_trackit.py

# Will use this to keep track of type opened
    # (1/2/3 == curved/curly/square)
    opentype = []

    typedict = {
        '(': (True, 1),
        ')': (False, 1),
        '[': (True, 2),
        ']': (False, 2),
        '{': (True, 3),
        '}': (False, 3)
    }

    for char in s:
        do_open, type = typedict[char]
    //   True   , 1  //

        if do_open:
            opentype.append(type)

        else:
            if not opentype:            # Nothing to close - fail
                return False

            elif type == opentype[-1]:  # Check against last opened type
                opentype.pop()          # Successful close
            else:
                return False            # Any bad close quits immediately

    # Check that we did close everything we opened
    if not opentype:
        return True
    else: