Questions tagged [palindrome]

Any sequence of units (typically letters or numbers) that are read the same way forward or backward.

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11
votes
5answers
866 views

Easy to read palindrome checker

I made a palindrome checker that's supposed to be designed to be simple and easy to read. Please let me know what you think. I believe the time complexity is \$\mathcal{O}(n)\$ but I'm not too sure ...
2
votes
1answer
56 views

Optimizing code solution for Palindrome Index-Hackerrank

I submitted my solution for palindrome Index coding challenge but I get "test cases terminated due to time out error". My code is working and so I don't know what else to do to optimize it. Please ...
2
votes
0answers
23 views

HackerRank's Challenging Palindromes solution times out for certain tests

I am trying to solve the Challenging Palindromes problem from HackerRank. The code that I have got so far fails only for large inputs due to timeout, every other test it passes successfully. The ...
3
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3answers
6k views

Finding the longest palindromic substring

I have the following code that works correctly. I am wondering if there is a simpler way to go about implementing my solution and/or if there is anything that looks non-standard in my code. If anyone ...
4
votes
1answer
46 views

A fast generator of palindrome dates in chronological order

02/02/2020 is a palindrome day because reading the date left-to-right or right-to-left still refers to the same calendar date. And because it doesn't matter whether you use the DD/MM/YYYY format or ...
6
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3answers
1k views

Determine whether an integer is a palindrome

The task Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: ...
9
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5answers
3k views

Palindrome checker program

I've been studying Java for some days and I'm just now starting to make some simple programs, I'd like to know if there's any 'noob' mistakes or habits that I could avoid. In other words: how could ...
3
votes
2answers
3k views

Largest palindrome made from the product of 3-digit numbers

I am given a task to write a program to find the largest palindrome made from the product of two 3-digit numbers. How can I improve this code? ...
7
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2answers
1k views

Python palindrome program

I have written a palindrome program. And I was just wondering if it correct? I checked using the words racecar and madam, and it says they are palindromes. I have also tested nonpalindrome words and ...
0
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1answer
2k views

Determining whether a string can be rearranged into a palindrome

For a string, count the number of occurences of each character. If at most one character has odd count then the string can be a palindrome else it's not. ...
3
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0answers
81 views

Longest palindrome code in C# takes time out on LeetCode

I like to request a review of the code below, which is my attempt at answering the question here on LeetCode site. The code passes 43 tests, but it times out on the next one. I copied and ran the test ...
16
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3answers
15k views

Return the largest palindrome from the string

Here is the question: find the largest palindrome from a string. Ex: ABCBAHELLOHOWRACECARAREYOUILOVEUEVOLIIAMAIDOINGGOOD Result: ...
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0answers
48 views

How do I optimize memoization in order to find longest palindromic substring?

I want to find the longest palindromic substring using dynamic programming in Python3. The strings can be as large as this string. I have seen other questions on this problem that successfully solve ...
0
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3answers
71 views

Basic Palindrome check comparing chars

I've seen variations of this assignment where you reverse a string to match it to the original to find out if it is a palindrome, but this version I made only iterates through half of the string ...
4
votes
2answers
432 views

Longest Palindromic Substring better approach

I have encountered to this question and applied a brute force algorithm off top of my head and couldn't find a better optimized solution. I was hoping I could get some insight to implement a better ...
3
votes
3answers
6k views

Reverse digits and add until a palindrome appears

The following code is a C solution to the following problem UVA 10018. The Problem The "reverse and add" method is simple: choose a number, reverse its digits and add it to the original. If ...
6
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3answers
558 views

CTCI Chapter 1 : Palindrome Permutation

Below is my code for the problem 1.4 in CTCI. I would like a review of my code and if my approach to the problem is correct. Problem Statement: Palindrome Permutation: Given a string, write a ...
3
votes
1answer
87 views

Project Euler - Problem No.4 - Largest palindrome product

according to the problem: A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99. Find the largest palindrome made ...
7
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4answers
6k views

Find palindromic substrings as efficiently as possible

I've written a function to calculate all the distinct substrings of a given string, that are palindromes. The string is passed as the argument to the function. For example, the string abba is a ...
10
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4answers
9k views

Project Euler #4 - Largest Palindrome Product

Problem Statement: A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99. Find the largest palindrome made from ...
4
votes
3answers
2k views

Palindrome test

This is some code that determines if a string of characters is a palindrome or not. My professor says that there is a performance issue with the program, but I can't quite put my finger on it. Can ...
3
votes
3answers
456 views

Check if a string is palindrome or two strings are the opposite of each other

I made a function which checks if a word is the opposite of each other (ex: word and drow) and then realized that with minor changes it could also be used to detect if a word is palindrome. They both ...
3
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2answers
293 views

Calculate the largest palindromic number from the product of two 6-digit numbers (100000 to 999999)

Are there any efficient ways to solve this problem, for example using bitwise operator? ...
4
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2answers
4k views

Check if a string is a permutation of a palindrome using Python

This is a solution to exercise 1.4 from Cracking the Coding Interview written using Python 3. Given a string, write a function to check if it is a permutation of a palindrome. Example: 'Tact Coa' ...
4
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1answer
135 views

Return whether a string is a palindrome if you can delete at most k elements

The task: Given a string which we can delete at most k, return whether you can make a palindrome. For example, given 'waterrfetawx' and a k of 2, you could delete f and x to get '...
3
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1answer
311 views

Palindromic partitions solution

Task Find the smallest number of cuts required to break a string into a set of valid palindromes. For example: ababbbabbababa becomes a|babbbab|b|ababa (cuts = 3) partytrapb becomes partytrap|b (...
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2answers
73 views

Palindrome Pairs

The task is taken from leetcode Given a list of unique words, find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] + words[j] ...
3
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0answers
198 views

Longest Palindrome Substring: Where is the dynamic programming? [closed]

In this LeetCode problem, Longest Palindromic Substring, it is listed under Dynamic Programming for Google interview preparation. My understanding of dynamic programming is roughly "recursion + ...
4
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4answers
181 views

Largest Palindrome Product - Project Euler #4

This is my code for Project Euler Problem #4 The question: A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99. Find ...
0
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1answer
63 views

Why does my function think that “uiouioiu”is a plaindrome? [closed]

I was reading Introduction to Computation and Programming using Python and there in an exercise, we had to write a function which would tell us if a given word is a palindrome or not, recursively. ...
4
votes
2answers
6k views

Check if string can be rearranged into a palindrome

I created a function to test whether a single word string can be a rearranged into a palindrome (doesn't have to be a real word). My logic was if the string has an even number of letters, then each ...
5
votes
2answers
6k views

Finding the next palindrome of a number string

Here is the problem: A positive integer is called a palindrome if its representation in the decimal system is the same when read from left to right and from right to left. For a given positive ...
1
vote
1answer
80 views

Check if given integer is a palindrome

This code checks if the given integer is a palindrome. If it is, prints given integer is a palindrome else, not a palindrome: ...
1
vote
4answers
209 views

Read a palindrome of unknown length

I have a task to write the function: int read_palindrome(); // input comes from stdin which will read one line from standard input and returns 1 if the line is a ...
15
votes
5answers
5k views

Palindrome checking function

I recently did a little task for fun that required me to create a class to determine if a word is a palindrome or not. I know this is quite simple, but I'd be interested to know if a real developer (I'...
2
votes
1answer
174 views

Find palindromes in circular rotated string

I'm trying to tackle a programming challenge to determine how many palindromes exist in a given string that is being rotated character by character. My solution works, but it's too slow, and I'm ...
6
votes
2answers
18k views

Find all distinct palindromic sub-strings for a given string

I was solving a question where I had to find all possible unique palindromes of size greater than 1 for a string. I was able to come up with the solution shown below. If I am not mistaken it is an \$...
3
votes
4answers
3k views

Find longest Palindrome substring

I am preparing for technical interview and I found this question on geeksforgeeks, but I did not understand their solution. So, I have written my own solution. I want to optimize this code. ...
10
votes
2answers
208 views

Determining if a string can be permuted to a palindrome

I am going through Elements of Programming Interview by Aziz, Lee and Prakash one of the questions is how to determine if a string can be permuted to a palindrome. For example ...
2
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0answers
182 views

Longest Palindromic Substring challenge

My code is a mix-up between dynamic programming with the HashMap and brute force with the way I reach out the results and substring. I don't know how to optimize my ...
4
votes
2answers
80 views

Solve Project Euler #4 in PHP

A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99. Find the largest palindrome made from the product of two 3-digit ...
3
votes
5answers
16k views

Check if a given string can be a palindrome by altering some character without using a library function

I was asked in an interview to write code to check if a given string is a palindrome or can be a palindrome by altering some character without using library function. My logic is to: Compare 1st <...
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1answer
83 views

Find the first palindrome larger than the given number

Question Input number of test cases. Input each test case and output its next palindrome number. Link: https://www.spoj.com/problems/PALIN/ Language Used: C++14 (gcc 6.3) My code ...
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1answer
47 views

A program that checks for Palindromness

Yes, I made it up. This program checks if an entered string is a palindrome or not by assigning a char variable the characters ...
2
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2answers
140 views

Find a palindromic string in C

This program tests whether a string is a palindrome or not. Can there be any improvements or shortcuts that can be used in the program. You can give any type of string as input. The program finds does ...
8
votes
4answers
1k views

Test if a string is a palindrome

I got this out of an article on interviews / code challenges. The challenge text goes like this: A palindrome is a word, phrase, number, or other sequence of characters which reads the same ...
10
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5answers
443 views
7
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3answers
1k views

The Next Palindromic number

I have incremented an integer in the function nextpalin() and converted it into a std::string for finding whether it's a ...
0
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1answer
153 views

Find largest palindrome from the product of two 3-digit numbers

I think this is a good solution to finding the largest numeric palindrome that can be formed from the product of two 3-digit numbers... But it seems like there are some improvements that we could make ...
7
votes
1answer
3k views

Check if a given linked list is palindrome

I am solving interview questions from here. Problem :Given a singly linked list, determine if its a palindrome. Return 1 or 0 denoting if its a palindrome or not, respectively. Notes:Expected ...

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