[deceptively nasty] Palindrome Index

This problem is prima facie really easy looking. But its a snake waiting to bite!

What I did initially was to initialize two variables, i = 0 and j = len(s) - 1 (start and end of s).
On each iteration of a while loop (while i < floor(len(s) / 2)), compare values s[i] and s[j] and if they are equal, we are good.

But if they are not equal, one of the two things can occur. Either s[i] must be the odd letter, or s[j]. For this the natural approach is to check the next letter, and see if they match, that is:

1. compare s[i + 1] and s[j]
2. compare s[i] and s[j - 1]

If 1. is true, then s[i] must be removed, and if 2 is true, s[j] must be removed.

Easy, right?
WRONG!

Consider the following testcases:

cwwcw
wcwwc

The above logic will give the wrong output for these cases.

It turns out, conditions 1. and 2. are NOT sufficient for determining which letter is the odd one out. We must also check the next pair of elements as well. The correct conditions are:

1. if s[i] == s[j - 1] and s[i + 1] == s[j - 2]
2. if s[i + 1] == s[j] and s[i + 2] == s[j - 1]

These correctly determine which out of s[i] and s[j] is the odd one out. Deceptively nasty indeed!