#!/usr/bin/env python
#计算对称子串长度
def count_sym(s):
length=len(s)
list_s=[]
for i in range(length-1):
if s[i]==s[i+1]:
count=2
key=2i+1
while i-1 >=0 and key-i+1 <=length-1:
i=i-1
if s[i]!=s[key-i]:
break;
count=count+2
list_s.append(count)
try:
if s[i]==s[i+2]:
count=3
key=2i +2
while i-1>=0 and key-i+1 <=length-1:
i=i-1
if s[i]!=s[key-i]:
break
count=count+2
list_s.append(count)
except IndexError:
continue
return max(list_s)

print(count_sym(‘0o1o0’))
print(count_sym(‘22’))