The expand-around-center approach checks every character (and every gap between characters) as a potential palindrome center and expands outward to verify palindromes, resulting in repeated character comparisons and a worst-case time complexity of O(n²).

In contrast, Manacher’s Algorithm optimizes this process by transforming the string and using palindrome symmetry to reuse previously computed information, thereby eliminating redundant expansions and achieving a linear time complexity of O(n).
in the code 
C -> center of the rightmost palindrome
R -> right boundary of rightmost Palindrome