### Check whether string is palindrome or not palindrome character string    Posted: 5 years ago Edit answers (1) views (1973)

Write a function to check that given string is palindrome or not.

 Posted: 5 years ago Updated: 5 years ago 0 0 Edit A string is a palindrome if it can be read the same way in either forward or reverse direction. $$e.g$$, $$kayak$$'. It reads the same ($$k$$ - $$a$$ - $$y$$ - $$a$$ - $$k$$) from either direction. The algorithm works as : Initialize two pointers - one from the beginning of the string and the other from the end. Compare the characters in both the pointers until the first pointer is less than the second one. If they are same, increment the first pointer and decrement the second one. If they are not same, return false. Time complexity = $$O(n)$$.public boolean checkStringIsPalindrome(String input){ /* Initialize first ponter */ int pointer1 = 0; /* Initialize second ponter */ int pointer2 = input.length - 1; while(pointer1 < pointer2){ /* check the characters at the two pointers */ /* Ignore white space */ if(input.charAt(pointer1) == ' ') pointer1++; if(input.charAt(pointer2) == ' ') pointer2--; /* If the characters at the two pointers does not match - Not a palindrome */ if(input.charAt(pointer1) != input.charAt(pointer2)){ return false; break; }else{ pointer1++; pointer2--; } } /* Yes, its a palindrome */ return true; } < Better approach > Using one pointer variablepublic boolean checkStringIsPalindrome(String input){ for (int i = 0;i < input.length / 2) + 1; ++i){ if (input.charAt(i) != input.charAt(input.length - i - 1)) return false; } return true; }`