You are given a String input. You are to find the longest substring of input such that the reversal of the substring is also a substring of input. In case of a tie, return the string that occurs earliest in input.
-The substring and its reversal may overlap partially or completely.
-The entire original string is itself a valid substring (see example 4).
-input will contain between 1 and 50 characters, inclusive.
-Each character of input will be an uppercase letter ('A'-'Z').
We see that the reverse of BCDEF is FEDCB, which appears later in the string.
The best we can do is find a one character substring, so we implement the tie-breaker rule of taking the earliest one first.
The string ABA is a palindrome (it's its own reversal), so it meets the criteria.
The similar as above.
Here, the entire string is its own reversal.