擅长:python、mysql、java
<pre><code>brmap = dict(['()', '[]', '{}'])
closebr = set(brmap.values())
def check_brackets(expr):
stack = []
for c in expr:
if c in brmap:
stack.append(brmap[c])
elif c in closebr and (not stack or stack.pop() != c):
return False
return not stack
</code></pre>