def unique_in_order(s):
if len(s) < 1:
return []
prev_sym = s[0]
result = [prev_sym]
for sym in s[1:]:
if sym == prev_sym:
continue
result.append(sym)
prev_sym = sym
return result
print(unique_in_order('AAAABBBCCDAABBB'))
ZGVmIHVuaXF1ZV9pbl9vcmRlcihzKToKCWlmIGxlbihzKSA8IDE6CgkJcmV0dXJuIFtdCglwcmV2X3N5bSA9IHNbMF0KCXJlc3VsdCA9IFtwcmV2X3N5bV0KCWZvciBzeW0gaW4gc1sxOl06CgkJaWYgc3ltID09IHByZXZfc3ltOgoJCQljb250aW51ZQoJCXJlc3VsdC5hcHBlbmQoc3ltKQoJCXByZXZfc3ltID0gc3ltCglyZXR1cm4gcmVzdWx0CgpwcmludCh1bmlxdWVfaW5fb3JkZXIoJ0FBQUFCQkJDQ0RBQUJCQicpKQ==