This can be solved in O(n^2) using dynamic programming. Basically, the problem is about building the longest palindromic subsequence in x[i…j] using the longest subsequence for x[i+1…j], x[i,…j-1] and x[i+1,…,j-1] (if first and last letters are the same). Firstly, the empty string and a single character string is trivially a palindrome. Notice that for a … Read more
function palindrome(str) { var len = str.length; var mid = Math.floor(len/2); for ( var i = 0; i < mid; i++ ) { if (str[i] !== str[len – 1 – i]) { return false; } } return true; } palindrome will return if specified word is palindrome, based on boolean value (true/false) UPDATE: I opened … Read more
The Linear solution can be found in this Way :: Prequisities: (1).You must know how to construct the suffix array in O(N) or O(NlogN) time. (2).You must know how to find the standard LCP Array ie. LCP between adjacent Suffixes i and i-1 ie . LCP [i]=LCP(suffix i in sorted array, suffix i-1 in sorted … Read more
A pythonic way to determine if a given value is a palindrome: str(n) == str(n)[::-1] Explanation: We’re checking if the string representation of n equals the inverted string representation of n The [::-1] slice takes care of inverting the string After that, we compare for equality using ==
I agree that the logic isn’t quite right in the explanation of the link. I give some details below. Manacher’s algorithm fills in a table P[i] which contains how far the palindrome centered at i extends. If P[5]=3, then three characters on either side of position five are part of the palindrome. The algorithm takes … Read more
Why not just: public static boolean istPalindrom(char[] word){ int i1 = 0; int i2 = word.length – 1; while (i2 > i1) { if (word[i1] != word[i2]) { return false; } ++i1; –i2; } return true; } Example: Input is “andna”. i1 will be 0 and i2 will be 4. First loop iteration we will … Read more
You can find the the longest palindrome using Manacher’s Algorithm in O(n) time! Its implementation can be found here and here. For input String s = “HYTBCABADEFGHABCDEDCBAGHTFYW1234567887654321ZWETYGDE” it finds the correct output which is 1234567887654321.
The answer to this question is that “it is impossible”. More specifically, the interviewer is wondering if you paid attention in your computational theory class. In your computational theory class you learned about finite state machines. A finite state machine is composed of nodes and edges. Each edge is annotated with a letter from a … Read more