Code: Search a Reverse Substring

    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.

Notes
    -The substring and its reversal may overlap partially or completely.
    -The entire original string is itself a valid substring (see example 4).
Constraints
    -input will contain between 1 and 50 characters, inclusive.
    -Each character of input will be an uppercase letter ('A'-'Z').
Examples
0) "XBCDEFYWFEDCBZ"
    Returns: "BCDEF"
    We see that the reverse of BCDEF is FEDCB, which appears later in the string.
1) "XYZ"
    Returns: "X"
    The best we can do is find a one character substring, so we implement the tie-breaker rule of taking the earliest one first.
2) "ABCABA"
    Returns: "ABA"
    The string ABA is a palindrome (it's its own reversal), so it meets the criteria.
3) "FDASJKUREKJFDFASIREYUFDHSAJYIREWQ"
    Returns: "FDF"
    The similar as above.
4) "ABCDCBA"
    Returns: "ABCDCBA"
    Here, the entire string is its own reversal.

class ReverseSubstring
}

Results are:

BCDEF

ABA

FDF

ABCDCBA