我的解法
我的解法不够直观, 而且写起来繁琐.
class Solution(object):
def isValid(self, s):
"""
:type s: str
:rtype: bool
"""
stack = []
for ch in s:
if ch=='(' or ch=='[' or ch=='{':
stack.append(ch)
elif ch == ')' and len(stack) > 0 and stack[-1] == '(':
stack.pop()
elif ch == ']' and len(stack) > 0 and stack[-1] == '[':
stack.pop()
elif ch == '}' and len(stack) > 0 and stack[-1] == '{':
stack.pop()
else:
return False
if len(stack) == 0:
return True
else:
return False
高效算法
class Solution:
def isValid(self, s):
d = {'}': '{', ']': '[', ')': '('}
stk = [' ']
for c in s:
c2 = d.get(c, '')
if stk[-1] == c2:
stk.pop()
elif c2:
return False
else:
stk.append(c)
return len(stk) == 1
