Given a string S, find the longest palindromic substring in S.
Substring of string S:
0 <= i <= j < len(S)
A string which reads the same backwards. More formally, S is palindrome if
reverse(S) = S.
Incase of conflict, return the substring which occurs first ( with the least starting index ).
Input : "aaaabaaa" Output : "aaabaaa"
NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a doubt? Checkout Sample Codes for more details.