#week10_chap06_10

def is_stack_full():
    global SIZE, stack, top
    if top == SIZE-1:
        return True
    else :
        return False


def is_stack_empty():
	global SIZE, stack, top
	if top == -1:
		return True
	else :
		return False


def push(data):
	global SIZE, stack, top
	if is_stack_full():
		print("스택이 꽉 찼습니다.")
		return
	top += 1
	stack[top] = data


def pop():
	global SIZE, stack, top
	if is_stack_empty():
		print("스택이 비었습니다.")
		return None
	data = stack[top]
	stack[top] = None
	top -= 1
	return data


def peek():
	global SIZE, stack, top
	if is_stack_empty():
		print("스택이 비었습니다.")
		return None
	return stack[top]


def checkBracket(expr):
	for ch in expr:  # '(A+B)' True,  ')A+B(' False, '((A+B)-C' False
		if ch in '([{<':
			push(ch)
		elif ch in ')]}>':
			out = pop()
			if ch == ')' and out == '(':
				pass
			elif ch == ']' and out == '[':
				pass
			elif ch == '}' and out == '{':
				pass
			elif ch == '>' and out == '<':
				pass
			else:
				return False
		else:
			pass
	if is_stack_empty():
		return True
	else:
		return False


SIZE = 100
stack = [ None for _ in range(SIZE) ]
top = -1

if __name__ == "__main__":
	exprAry = ['(A+B)', ')A+B(', '((A+B)-C', '(A+B]', '(<A+{B-C}/[C*D]>)']

	for expr in exprAry:
		top = -1
		print(expr, '==>', checkBracket(expr))