bracket sequence checker

brckcheck.py

# rather funny that I give my students exactly this task :)
from typing import Iterable


def check_brackets(brckt_seq: Iterable[str]) -> bool:
	"""
	Check whether bracket sequence is correct or not

	:param brckt_seq: str of brackets (with different types)
	:return: True if bracket sequence is correct, False otherwise
	"""

	# maybe should be parameter, depends if it changeable
	available_brackets = {
		')': '(',
		'}': '{',
		'>': '<',
		']': '['
	}

	stack = list()

	# save every opening bracket to stack and pop&check on every closing bracket
	for i in brckt_seq:
		if i in available_brackets:
			if not stack:
				# empty stack -> there were no corresponding opening bracket
				return False

			# non-corresponding bracket returned from stack
			if stack.pop() != available_brackets[i]:
				return False
		else:
			stack.append(i)

	if stack:
		# there are odd opening brackets
		return False

	return True