Questions tagged [palindrome]

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

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Recursive Palindrome in JavaScript

Would someone review this code, and confirm that it is indeed recursive? I'm learning computer science and going through different types of algorithms. Right now, I'm focusing on recursion want to ...
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Algorithm For Longest Palindrome

I made an brute force algorithm to find the longest palindrome within the string. This palindrome is a substring of the input. Below is the code. ...
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1answer
88 views

Check if string is palindrome LeetCode

LeetCode 125 requires receiving a string and checking if it is a valid palindrome. I have done this and am confident with an int and a single word, but this question requires the use a of a sentence ...
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1answer
91 views

palindrome code in C times out in program challenge?

Hello I am making a code in C to find the value of the last sequence of palindromes of a specified size (d) and I need to optimize this code as it is for an ...
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LeetCode on Longest Palindromic Substring in Python

This is a programming question from LeetCode: Given a string s, return the longest palindromic substring in s. Example 1: Input: s = "babad" Output: "bab" Note: "aba" is ...
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999 views

Check if a binary tree is symmetric in Python

I have solved the following Leetcode problem. Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree [1,2,2,3,4,4,3] is symmetric....
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Palindrome Algorithm and JUnit 5 Tests

I have a "Palindrome" class that has some functions for verifying if certain things are Palindromes. For the verification, I have 2 different algorithms, one being recursive and the other ...
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4answers
689 views

Python palindrome checker function

For practice purposes I implemented a function that checks for palindromes: ...
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1answer
66 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 ...
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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 ...
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1answer
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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 ...
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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 ...
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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 ...
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59 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 ...
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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 ...
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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 ...
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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 ...
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1answer
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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 ...
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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 ...
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370 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? ...
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1answer
320 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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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] ...
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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 + ...
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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 ...
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1answer
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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. ...
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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: ...
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1answer
155 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 '...
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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 ...
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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 ...
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1answer
92 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: ...
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4answers
236 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 ...
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1answer
200 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 ...
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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 ...
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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 ...
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2answers
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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 ...
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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. ...
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1answer
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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
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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 ...
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2answers
273 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 ...
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448 views

Circles of numbers

I have a function: ...
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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 ...
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1answer
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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 ...
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1answer
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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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Next palindromic number

I wrote a function that takes a number and finds the next palindromic number. Time complexity is currently O(n2), which is really bad. How could one make this function more efficient? ...
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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'...
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Count palindrome substrings

Given a string S, count and return the number of substrings of S that are palindromes. Single length substrings are also palindromes. We just have to count the substring that are palindrome. ...
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Palindrome algorithm

This code could be better? This is the algorithm: Compare the 1st character to the last character Compare the 2nd character to the second last character and so on Stop when the middle of the ...
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2answers
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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? ...
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2answers
1k views

Finding palindromic strings of even length

Given a string of digits. Find the length of longest substring of even length i.e. 0,2,... which is a palindrome or which can be rearranged to form a palindrome (see example below). Here is my code: ...

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