An encoded string is given. The pattern in which the strings are encoded is as follows: <count>[sub_str]
means that the substring 'sub_str'
appears count
times. The task is to decode the given string.
"1[b]"
should return "b"
.
"2[ab]"
should return "abab"
.
"2[a2[b]]"
should return "abbabb"
.