1544. Make The String Great
class Solution:
def makeGood(self, s: str) -> str:
if len(s) == 0:
return s
res = []
for c in s:
if res:
if res[-1].upper() == c.upper():
if (res[-1].isupper() and c.islower()) or (res[-1].islower() and c.isupper()):
res.pop()
continue
res.append(c)
return ''.join(res)