def get_f_l(s_length,s,list_all,last_d):
max_l=0
first_d=0
last_d=0
for i in range(len(list_all)):
if((i+1)==len(list_all)):
break
for j in range(i+1,len(list_all)):
diff=list_all[j]-list_all[i]+1
if(list_all[i]==0):
if(list_all[j]==s_length-1):
if(s==s[::-1]):
return 0,list_all[j]
else:
if(s[:list_all[j]+1]==s[list_all[j]::-1]):
if(diff>max_l):
max_l=diff
first_d=0
last_d=list_all[j]
else:
if(list_all[j]==s_length-1):
if(s[list_all[i]:]==s[list_all[j]:list_all[i]-1:-1]):
if(diff>max_l):
max_l=diff
first_d=list_all[i]
last_d=list_all[j]
else:
if(s[list_all[i]:list_all[j]+1]==s[list_all[j]:list_all[i]-1:-1]):
if(diff>max_l):
max_l=diff
first_d=list_all[i]
last_d=list_all[j]
return first_d,last_d
def solution(s):
s_length=len(s)
max_len=0
f=0
l=0
s_x=set(s)
for i in s_x:
last_d=s.rfind(i)
list_all=[]
oper_s=s
i_num=0
while(True):
x=s.find(i,i_num)
if(not x==-1):
i_num=x+1
list_all.append(x)
else:
break
if(len(list_all)==1):
continue
first_d,last_d=get_f_l(s_length,s,list_all,last_d)
diff=last_d-first_d
if(diff>max_len):
f=first_d
l=last_d
max_len=diff
return s[f:l+1]
s="abccccde"
print(solution(s))
