Given a string of lowercase English alphabets. The task is to check if there exists any subsequence in the string which is not a palindrome. If there is at least 1 subsequence which is not a palindrome then print YES, otherwise print NO.
Input : str = "abaab" Output : YES Subsequences "ab" or "abaa" or "aab", are not palindrome. Input : str = "zzzz" Output : NO All possible subsequences are palindrome.
The main observation is that if the string contains at least two distinct characters, then there will always be a subsequence of length at least two which is not a palindrome. Only if all the characters of the string are same then there will not be any subsequence which is not a palindrome. Because in an optimal way we can choose any two distinct characters from a string and place them in same order one after each to form a non-palindromic string.
Below is the implementation of above approach:
Time Complexity: O(N), where N is the length of the string.
- Check whether a subsequence exists with sum equal to k if arr[i]> 2*arr[i-1]
- Queries to check if string B exists as substring in string A
- Check if any anagram of a string is palindrome or not
- C Program to Check if a Given String is Palindrome
- Check if a string is palindrome in C using pointers
- Check if a given string is a rotation of a palindrome
- Check whether the given string is Palindrome using Stack
- Check if it is possible to create a palindrome string from given N
- Recursive function to check if a string is palindrome
- Given two strings check which string makes a palindrome first
- Java program to check whether a string is a Palindrome
- Python program to check if a string is palindrome or not
- Python program to check if given string is vowel Palindrome
- TCP Client-Server Program to Check if a Given String is Palindrome
- Check if string can be rearranged so that every Odd length Substring is Palindrome
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.