Best O(N) Python Solution Explained
O(N) Python Solution\n\ndef breakPalindrome(self, palindrome: str) -> str:\n\tn = len(palindrome) # store palindrome length\n\tif n == 1: # no way to make 1 let
**O(N) Python Solution**\n```\ndef breakPalindrome(self, palindrome: str) -> str:\n\tn = len(palindrome) # store palindrome length\n\tif n == 1: # no way to make 1 letter not a palindrome\n\t\treturn ""\n\tfor i in range(n//2): # go through the first half of the palindrome\n\t\tif palindrome[i] != "a": # if it is not an "a" then we can make it lexicographically smaller\n\t\t\treturn palindrome[:i] + "a" + palindrome[i+1:] # replace character with an "a"\n\treturn palindrome[:-1] + "b" # if all "a", then replace the last one with a "b"\n```\n\n**Explanation**\nThe idea behind this solution is that we want to make the string lexicographically smaller, so whenever there is an opportunity to turn a character which is not ```a``` into ```a```, we should. We only need to check the first ```n//2``` indices because we know that the input is a palindrome, so anything in the first ```n//2``` spots will be mirrored. If the string has an odd length, we cannot change the middle character since then the string would still be a palindrome. If we never find a character which is not ```a```, then we have to change one of the characters to ```b```. We want to add this to the end of the string since that minimizes the lexicographic value. We also have to check the length of ```palindrome``` is ```1``` since then there is no way to turn it into a non-palindrome, so we return ```""```.\n\n**Complexity**\nThis solution takes ```O(n)``` time since the number of characters we need to check scales with the length of ```palindrome```. It takes constant space since the memory we use does not change with the size of ```palindrome```.\n\n**Thanks for Reading!**\nIf this post has been helpful, please consider upvoting! If you have any questions, please feel free to ask in the comments and I will try to answer them. Also, if I made any mistakes or there are other optimizations, methods I didn\'t consider, etc. please let me know!
['Greedy', 'Python']